diff --git a/CHANGES.md b/CHANGES.md
index 70eb28e..191806c 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -3,6 +3,16 @@ Change Log
 
 ### 1.3.5 ????-??-??
 
+* Improved handling of primitives with different attributes using the same material. Materials are now duplicated. [#163](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/163)
+* Fixed a bug where primitives without texture coordinates could use materials containing textures. Those textures are now removed. [#163](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/163)
+* Improved parsing of faces with mismatching attributes. [#163](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/163)
+* Added ability to use the first material in the mtl file when the obj is missing `usemtl`. [#163](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/163)
+* Fixed handling of unnormalized input normals. [#163](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/163)
+* Fixed handling of materials where the diffuse and ambient texture are the same. [#163](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/163)
+* Fixed handling of `usemtl` when appearing before an `o` or `g` token. [#163](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/163)
+* Fixed loading faces that contain less than 3 vertices. [#163](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/163)
+* Attempt to load missing materials and textures from within the same directory as the obj. [#163](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/163)
+* Fixed loading mtllib paths that contain spaces. [#163](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/163)
 * Improved handling of materials with alpha. If the alpha value is 0.0 it is now treated as 1.0. [#164](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/164)
 
 ### 1.3.4 2018-10-16
@@ -13,6 +23,8 @@ Change Log
 ### 1.3.3 2018-09-19
 
 * Fixed handling of objs with mismatching attribute layouts. [#154](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/154)
+* Fixed parsing mtl textures that contain texture map options. [#151](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/151)
+* Fixed normalization of Windows paths when running the converter on Linux. [#151](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/151)
 
 ### 1.3.2 2018-06-07
 * Fixed greyscale images loading as alpha instead of luminance. [#144](https://github.com/AnalyticalGraphicsInc/obj2gltf/pull/144)
diff --git a/lib/createGltf.js b/lib/createGltf.js
index f183757..c1ef37d 100644
--- a/lib/createGltf.js
+++ b/lib/createGltf.js
@@ -3,8 +3,9 @@ var Cesium = require('cesium');
 var path = require('path');
 var Material = require('./Material');
 
-var defined = Cesium.defined;
+var clone = Cesium.clone;
 var defaultValue = Cesium.defaultValue;
+var defined = Cesium.defined;
 var WebGLConstants = Cesium.WebGLConstants;
 
 module.exports = createGltf;
@@ -27,6 +28,9 @@ function createGltf(objData, options) {
     var vertexBufferViewId = 'bufferView_vertex';
     var indexBufferViewId = 'bufferView_index';
 
+    // Split materials used by primitives with different types of attributes
+    materials = splitIncompatibleMaterials(nodes, materials);
+
     var gltf = {
         accessors : {},
         asset : {},
@@ -290,23 +294,8 @@ function createGltf(objData, options) {
                 primitive.uvs = undefined;
                 primitive.indices = undefined;
 
-                if (!defined(materialId)) {
-                    // Create a default material if the primitive does not specify one
-                    materialId = 'default';
-                }
-
                 var material = materials[materialId];
-                material = defined(material) ? material : new Material();
                 var gltfMaterial = gltf.materials[materialId];
-                if (defined(gltfMaterial)) {
-                    // Check if this material has already been added but with incompatible shading
-                    var normalShading = (gltfMaterial.extensions.KHR_materials_common.technique !== 'CONSTANT');
-                    if (hasNormals !== normalShading) {
-                        materialId += (hasNormals ? '_shaded' : '_constant');
-                        gltfMaterial = gltf.materials[materialId];
-                    }
-                }
-
                 if (!defined(gltfMaterial)) {
                     gltf.materials[materialId] = createMaterial(material, hasNormals, options);
                 }
@@ -350,3 +339,75 @@ function createGltf(objData, options) {
 
     return gltf;
 }
+
+function primitiveInfoMatch(a, b) {
+    return a.hasUvs === b.hasUvs &&
+        a.hasNormals === b.hasNormals;
+}
+
+function cloneMaterial(material, removeTextures) {
+    material = clone(material, true);
+    if (removeTextures) {
+        material.ambientTexture = undefined;
+        material.emissionTexture = undefined;
+        material.diffuseTexture = undefined;
+        material.specularTexture = undefined;
+        material.specularShininessMap = undefined;
+        material.normalMap = undefined;
+        material.alphaMap = undefined;
+    }
+    return material;
+}
+
+function getSplitMaterialName(originalMaterialName, primitiveInfo, primitiveInfoByMaterial) {
+    var splitMaterialName = originalMaterialName;
+    var suffix = 2;
+    while (defined(primitiveInfoByMaterial[splitMaterialName])) {
+        if (primitiveInfoMatch(primitiveInfo, primitiveInfoByMaterial[splitMaterialName])) {
+            break;
+        }
+        splitMaterialName = originalMaterialName + '-' + suffix++;
+    }
+    return splitMaterialName;
+}
+
+function splitIncompatibleMaterials(nodes, materials) {
+    var splitMaterials = {};
+    var primitiveInfoByMaterial = {};
+    var nodesLength = nodes.length;
+    for (var i = 0; i < nodesLength; ++i) {
+        var meshes = nodes[i].meshes;
+        var meshesLength = meshes.length;
+        for (var j = 0; j < meshesLength; ++j) {
+            var primitives = meshes[j].primitives;
+            var primitivesLength = primitives.length;
+            for (var k = 0; k < primitivesLength; ++k) {
+                var primitive = primitives[k];
+                var hasUvs = primitive.uvs.length > 0;
+                var hasNormals = primitive.normals.length > 0;
+                var primitiveInfo = {
+                    hasUvs : hasUvs,
+                    hasNormals :  hasNormals
+                };
+                var originalMaterialName = defaultValue(primitive.material, 'default');
+                var splitMaterialName = getSplitMaterialName(originalMaterialName, primitiveInfo, primitiveInfoByMaterial);
+                primitive.material = splitMaterialName;
+                primitiveInfoByMaterial[splitMaterialName] = primitiveInfo;
+
+                var splitMaterial = splitMaterials[splitMaterialName];
+                if (defined(splitMaterial)) {
+                    continue;
+                }
+
+                var originalMaterial = materials[originalMaterialName];
+                if (defined(originalMaterial)) {
+                    splitMaterial = cloneMaterial(originalMaterial, !hasUvs);
+                } else {
+                    splitMaterial = new Material();
+                }
+                splitMaterials[splitMaterialName] = splitMaterial;
+            }
+        }
+    }
+    return splitMaterials;
+}
diff --git a/lib/loadMtl.js b/lib/loadMtl.js
index ac17648..3a04a10 100644
--- a/lib/loadMtl.js
+++ b/lib/loadMtl.js
@@ -86,10 +86,23 @@ function loadMtl(mtlPath) {
 
     return readLines(mtlPath, parseLine)
         .then(function() {
+            cleanupMaterials(materials);
             return materials;
         });
 }
 
+function cleanupMaterials(materials) {
+    for (var name in materials) {
+        if (materials.hasOwnProperty(name)) {
+            var material = materials[name];
+            if (material.diffuseTexture === material.ambientTexture) {
+                // OBJ models are often exported with the same texture in the diffuse and ambient slots but this is usually not desirable
+                material.ambientTexture = undefined;
+            }
+        }
+    }
+}
+
 function correctAlpha(alpha) {
     // An alpha of 0.0 usually implies a problem in the export, change to 1.0 instead
     return alpha === 0.0 ? 1.0 : alpha;
diff --git a/lib/loadObj.js b/lib/loadObj.js
index 8659507..b02bea2 100644
--- a/lib/loadObj.js
+++ b/lib/loadObj.js
@@ -78,6 +78,7 @@ function loadObj(objPath, options) {
     var node;
     var mesh;
     var primitive;
+    var activeMaterial;
 
     // All nodes seen in the obj
     var nodes = [];
@@ -125,6 +126,7 @@ function loadObj(objPath, options) {
 
     function addPrimitive() {
         primitive = new Primitive();
+        primitive.material = activeMaterial;
         mesh.primitives.push(primitive);
 
         // Clear the vertex cache for each new primitive
@@ -132,22 +134,42 @@ function loadObj(objPath, options) {
         vertexCount = 0;
     }
 
-    function useMaterial(name) {
-        // Look to see if this material has already been used by a primitive in the mesh
-        var material = getName(name);
+    function reusePrimitive(callback) {
         var primitives = mesh.primitives;
         var primitivesLength = primitives.length;
         for (var i = 0; i < primitivesLength; ++i) {
-            if (primitives[i].material === material) {
-                primitive = primitives[i];
-                clearVertexCache();
-                vertexCount = primitive.positions.length / 3;
-                return;
+            if (primitives[i].material === activeMaterial) {
+                if (!defined(callback) || callback(primitives[i])) {
+                    primitive = primitives[i];
+                    clearVertexCache();
+                    vertexCount = primitive.positions.length / 3;
+                    return;
+                }
             }
         }
-        // Add a new primitive with this material
         addPrimitive();
-        primitive.material = getName(name);
+    }
+
+    function useMaterial(name) {
+        activeMaterial = getName(name);
+        reusePrimitive();
+    }
+
+    function faceAndPrimitiveMatch(uvs, normals, primitive) {
+        var faceHasUvs = uvs[0].length > 0;
+        var faceHasNormals = normals[0].length > 0;
+        var primitiveHasUvs = primitive.uvs.length > 0;
+        var primitiveHasNormals = primitive.normals.length > 0;
+        return primitiveHasUvs === faceHasUvs && primitiveHasNormals === faceHasNormals;
+    }
+
+    function checkPrimitive(uvs, normals) {
+        var firstFace = primitive.indices.length === 0;
+        if (!firstFace && !faceAndPrimitiveMatch(uvs, normals, primitive)) {
+            reusePrimitive(function(primitive) {
+                return faceAndPrimitiveMatch(uvs, normals, primitive);
+            });
+        }
     }
 
     function getOffset(a, attributeData, components) {
@@ -269,16 +291,7 @@ function loadObj(objPath, options) {
     function addFace(vertices, positions, uvs, normals) {
         var i;
         var isWindingCorrect;
-
-        var firstFace = primitive.indices.length === 0;
-        var faceHasUvs = uvs[0].length > 0;
-        var faceHasNormals = normals[0].length > 0;
-        var primitiveHasUvs = primitive.uvs.length > 0;
-        var primitiveHasNormals = primitive.normals.length > 0;
-        if (!firstFace && (faceHasUvs !== primitiveHasUvs || faceHasNormals !== primitiveHasNormals)) {
-            // Discard faces that don't use the same attributes
-            return;
-        }
+        checkPrimitive(uvs, normals);
 
         if (vertices.length === 3) {
             isWindingCorrect = checkWindingCorrect(positions[0], positions[1], positions[2], normals[0]);
@@ -333,8 +346,8 @@ function loadObj(objPath, options) {
             var materialName = line.substring(7).trim();
             useMaterial(materialName);
         } else if (/^mtllib/i.test(line)) {
-            var paths = line.substring(7).trim().split(' ');
-            mtlPaths = mtlPaths.concat(paths);
+            var mtllibLine = line.substring(7).trim();
+            mtlPaths = mtlPaths.concat(getMtlPaths(mtllibLine));
         } else if ((result = vertexPattern.exec(line)) !== null) {
             var position = scratchCartesian;
             position.x = parseFloat(result[1]);
@@ -347,10 +360,12 @@ function loadObj(objPath, options) {
             positions.push(position.y);
             positions.push(position.z);
         } else if ((result = normalPattern.exec(line) ) !== null) {
-            var normal = scratchCartesian;
-            normal.x = parseFloat(result[1]);
-            normal.y = parseFloat(result[2]);
-            normal.z = parseFloat(result[3]);
+            var normal = Cartesian3.fromElements(parseFloat(result[1]), parseFloat(result[2]), parseFloat(result[3]), scratchNormal);
+            if (Cartesian3.equals(normal, Cartesian3.ZERO)) {
+                Cartesian3.clone(Cartesian3.UNIT_Z, normal);
+            } else {
+                Cartesian3.normalize(normal, normal);
+            }
             if (defined(axisTransform)) {
                 Matrix4.multiplyByPointAsVector(axisTransform, normal, normal);
             }
@@ -375,7 +390,9 @@ function loadObj(objPath, options) {
                     faceUvs.push(result[2]);
                     faceNormals.push(result[3]);
                 }
-                addFace(faceVertices, facePositions, faceUvs, faceNormals);
+                if (faceVertices.length > 2) {
+                    addFace(faceVertices, facePositions, faceUvs, faceNormals);
+                }
 
                 faceVertices.length = 0;
                 facePositions.length = 0;
@@ -398,17 +415,37 @@ function loadObj(objPath, options) {
             uvs = undefined;
 
             // Load materials and images
-            return finishLoading(nodes, mtlPaths, objPath, options);
+            return finishLoading(nodes, mtlPaths, objPath, defined(activeMaterial), options);
         });
 }
 
-function finishLoading(nodes, mtlPaths, objPath, options) {
+function getMtlPaths(mtllibLine) {
+    // Handle paths with spaces. E.g. mtllib my material file.mtl
+    var mtlPaths = [];
+    var splits = mtllibLine.split(' ');
+    var length = splits.length;
+    var startIndex = 0;
+    for (var i = 0; i < length; ++i) {
+        if (path.extname(splits[i]) !== '.mtl') {
+            continue;
+        }
+        var mtlPath = splits.slice(startIndex, i + 1).join(' ');
+        mtlPaths.push(mtlPath);
+        startIndex = i + 1;
+    }
+    return mtlPaths;
+}
+
+function finishLoading(nodes, mtlPaths, objPath, usesMaterials, options) {
     nodes = cleanNodes(nodes);
     if (nodes.length === 0) {
-        return Promise.reject(new RuntimeError(objPath + ' does not have any geometry data'));
+        throw new RuntimeError(objPath + ' does not have any geometry data');
     }
-    return loadMaterials(mtlPaths, objPath, options)
+    return loadMtls(mtlPaths, objPath, options)
         .then(function(materials) {
+            if (Object.keys(materials).length > 0 && !usesMaterials) {
+                assignDefaultMaterial(nodes, materials);
+            }
             var imagePaths = getImagePaths(materials);
             return loadImages(imagePaths, objPath, options)
                 .then(function(images) {
@@ -426,50 +463,90 @@ function normalizeMtlPath(mtlPath, objDirectory) {
     return path.normalize(path.join(objDirectory, mtlPath));
 }
 
-function outsideDirectory(filePath, objPath) {
-    return (path.relative(path.dirname(objPath), filePath).indexOf('..') === 0);
+function outsideDirectory(file, directory) {
+    return (path.relative(directory, file).indexOf('..') === 0);
 }
 
-function loadMaterials(mtlPaths, objPath, options) {
-    var secure = options.secure;
-    var logger = options.logger;
+function loadMtls(mtlPaths, objPath, options) {
     var objDirectory = path.dirname(objPath);
     var materials = {};
+
+    // Remove duplicates
+    mtlPaths = mtlPaths.filter(function(value, index, self) {
+        return self.indexOf(value) === index;
+    });
+
     return Promise.map(mtlPaths, function(mtlPath) {
         mtlPath = normalizeMtlPath(mtlPath, objDirectory);
-        if (secure && outsideDirectory(mtlPath, objPath)) {
-            logger('Could not read mtl file at ' + mtlPath + ' because it is outside of the obj directory and the secure flag is true. Using default material instead.');
-            return;
+        var shallowPath = path.join(objDirectory, path.basename(mtlPath));
+        if (options.secure && outsideDirectory(mtlPath, objDirectory)) {
+            // Try looking for the .mtl in the same directory as the obj
+            options.logger('The material file is outside of the obj directory and the secure flag is true. Attempting to read the material file from within the obj directory instead.');
+            return loadMtl(shallowPath)
+                .then(function(materialsInMtl) {
+                    Object.assign(materials, materialsInMtl);
+                })
+                .catch(function(error) {
+                    options.logger(error.message);
+                    options.logger('Could not read material file at ' + shallowPath + '. Using default material instead.');
+                });
         }
         return loadMtl(mtlPath)
-            .then(function(materialsInMtl) {
-                materials = Object.assign(materials, materialsInMtl);
+            .catch(function(error) {
+                // Try looking for the .mtl in the same directory as the obj
+                options.logger(error.message);
+                options.logger('Could not read material file at ' + mtlPath + '. Attempting to read the material file from within the obj directory instead.');
+                return loadMtl(shallowPath);
             })
-            .catch(function() {
-                logger('Could not read mtl file at ' + mtlPath + '. Using default material instead.');
+            .then(function(materialsInMtl) {
+                Object.assign(materials, materialsInMtl);
+            })
+            .catch(function(error) {
+                options.logger(error.message);
+                options.logger('Could not read material file at ' + shallowPath + '. Using default material instead.');
             });
     }, {concurrency : 10})
-        .thenReturn(materials);
+        .then(function() {
+            return materials;
+        });
+}
+
+function loadImagePath(imagePath, objPath, options) {
+    var objDirectory = path.dirname(objPath);
+    var shallowPath = path.join(objDirectory, path.basename(imagePath));
+    if (options.secure && outsideDirectory(imagePath, objDirectory)) {
+        // Try looking for the image in the same directory as the obj
+        options.logger('Image file is outside of the obj directory and the secure flag is true. Attempting to read the image file from within the obj directory instead.');
+        return loadImage(shallowPath, options)
+            .catch(function(error) {
+                options.logger(error.message);
+                options.logger('Could not read image file at ' + shallowPath + '. This image will be ignored');
+            });
+    }
+    return loadImage(imagePath, options)
+        .catch(function(error) {
+            // Try looking for the image in the same directory as the obj
+            options.logger(error.message);
+            options.logger('Could not read image file at ' + imagePath + '. Attempting to read the image file from within the obj directory instead.');
+            return loadImage(shallowPath, options);
+        })
+        .catch(function(error) {
+            options.logger(error.message);
+            options.logger('Could not read image file at ' + shallowPath + '. This image will be ignored.');
+        });
 }
 
 function loadImages(imagePaths, objPath, options) {
-    var secure = options.secure;
-    var logger = options.logger;
     var images = {};
     return Promise.map(imagePaths, function(imagePath) {
-        if (secure && outsideDirectory(imagePath, objPath)) {
-            logger('Could not read image file at ' + imagePath + ' because it is outside of the obj directory and the secure flag is true. Material will ignore this image.');
-            return;
-        }
-        return loadImage(imagePath, options)
+        return loadImagePath(imagePath, objPath, options)
             .then(function(image) {
                 images[imagePath] = image;
-            })
-            .catch(function() {
-                logger('Could not read image file at ' + imagePath + '. Material will ignore this image.');
             });
     }, {concurrency : 10})
-        .thenReturn(images);
+        .then(function() {
+            return images;
+        });
 }
 
 function getImagePaths(materials) {
@@ -494,6 +571,23 @@ function getImagePaths(materials) {
     return Object.keys(imagePaths);
 }
 
+function assignDefaultMaterial(nodes, materials) {
+    var defaultMaterial = Object.keys(materials)[0];
+    var nodesLength = nodes.length;
+    for (var i = 0; i < nodesLength; ++i) {
+        var meshes = nodes[i].meshes;
+        var meshesLength = meshes.length;
+        for (var j = 0; j < meshesLength; ++j) {
+            var primitives = meshes[j].primitives;
+            var primitivesLength = primitives.length;
+            for (var k = 0; k < primitivesLength; ++k) {
+                var primitive = primitives[k];
+                primitive.material = defaultValue(primitive.material, defaultMaterial);
+            }
+        }
+    }
+}
+
 function removeEmptyMeshes(meshes) {
     return meshes.filter(function(mesh) {
         // Remove empty primitives
diff --git a/specs/data/box-complex-material-alpha/alpha.png b/specs/data/box-complex-material-alpha/alpha.png
new file mode 100644
index 0000000..d04eb82
Binary files /dev/null and b/specs/data/box-complex-material-alpha/alpha.png differ
diff --git a/specs/data/box-complex-material-alpha/ambient.gif b/specs/data/box-complex-material-alpha/ambient.gif
new file mode 100644
index 0000000..1276823
Binary files /dev/null and b/specs/data/box-complex-material-alpha/ambient.gif differ
diff --git a/specs/data/box-complex-material-alpha/box-complex-material-alpha.mtl b/specs/data/box-complex-material-alpha/box-complex-material-alpha.mtl
new file mode 100644
index 0000000..5c598ff
--- /dev/null
+++ b/specs/data/box-complex-material-alpha/box-complex-material-alpha.mtl
@@ -0,0 +1,20 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl Material
+Ns 96.078431
+Ka 0.200000 0.200000 0.200000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.100000 0.100000 0.100000
+Ni 1.000000
+d 0.900000
+Tr 0.100000
+map_Ka ambient.gif
+map_Ke emission.jpg
+map_Kd diffuse.png
+map_Ks specular.jpeg
+map_Ns shininess.png
+map_Bump bump.png
+map_d alpha.png
+illum 2
diff --git a/specs/data/box-complex-material-alpha/box-complex-material-alpha.obj b/specs/data/box-complex-material-alpha/box-complex-material-alpha.obj
new file mode 100644
index 0000000..15d7f4a
--- /dev/null
+++ b/specs/data/box-complex-material-alpha/box-complex-material-alpha.obj
@@ -0,0 +1,46 @@
+# Blender v2.78 (sub 0) OBJ File: ''
+# www.blender.org
+mtllib box-complex-material-alpha.mtl
+o Cube
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+usemtl Material
+s off
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9/3 8/10/3 6/11/3 5/12/3
+f 5/13/4 6/14/4 2/15/4 1/16/4
+f 3/5/5 7/17/5 5/18/5 1/16/5
+f 8/19/6 4/6/6 2/15/6 6/20/6
diff --git a/specs/data/box-complex-material-alpha/bump.png b/specs/data/box-complex-material-alpha/bump.png
new file mode 100644
index 0000000..16ec3a9
Binary files /dev/null and b/specs/data/box-complex-material-alpha/bump.png differ
diff --git a/specs/data/box-complex-material-alpha/diffuse.png b/specs/data/box-complex-material-alpha/diffuse.png
new file mode 100644
index 0000000..8704966
Binary files /dev/null and b/specs/data/box-complex-material-alpha/diffuse.png differ
diff --git a/specs/data/box-complex-material-alpha/emission.jpg b/specs/data/box-complex-material-alpha/emission.jpg
new file mode 100644
index 0000000..e5c85a9
Binary files /dev/null and b/specs/data/box-complex-material-alpha/emission.jpg differ
diff --git a/specs/data/box-complex-material-alpha/shininess.png b/specs/data/box-complex-material-alpha/shininess.png
new file mode 100644
index 0000000..bfcf1a2
Binary files /dev/null and b/specs/data/box-complex-material-alpha/shininess.png differ
diff --git a/specs/data/box-complex-material-alpha/specular.jpeg b/specs/data/box-complex-material-alpha/specular.jpeg
new file mode 100644
index 0000000..661bf98
Binary files /dev/null and b/specs/data/box-complex-material-alpha/specular.jpeg differ
diff --git a/specs/data/box-complex-material/box-complex-material.mtl b/specs/data/box-complex-material/box-complex-material.mtl
index 5c598ff..1ab3601 100644
--- a/specs/data/box-complex-material/box-complex-material.mtl
+++ b/specs/data/box-complex-material/box-complex-material.mtl
@@ -16,5 +16,4 @@ map_Kd diffuse.png
 map_Ks specular.jpeg
 map_Ns shininess.png
 map_Bump bump.png
-map_d alpha.png
 illum 2
diff --git a/specs/data/box-diffuse-ambient-same/box-diffuse-ambient-same.mtl b/specs/data/box-diffuse-ambient-same/box-diffuse-ambient-same.mtl
new file mode 100644
index 0000000..cb21081
--- /dev/null
+++ b/specs/data/box-diffuse-ambient-same/box-diffuse-ambient-same.mtl
@@ -0,0 +1,14 @@
+# Blender MTL File: 'box.blend'
+# Material Count: 1
+
+newmtl Material
+Ns 96.078431
+Ka 0.000000 0.000000 0.000000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+map_Kd cesium.png
+map_Ka cesium.png
diff --git a/specs/data/box-diffuse-ambient-same/box-diffuse-ambient-same.obj b/specs/data/box-diffuse-ambient-same/box-diffuse-ambient-same.obj
new file mode 100644
index 0000000..5d52f28
--- /dev/null
+++ b/specs/data/box-diffuse-ambient-same/box-diffuse-ambient-same.obj
@@ -0,0 +1,46 @@
+# Blender v2.78 (sub 0) OBJ File: 'box.blend'
+# www.blender.org
+mtllib box-diffuse-ambient-same.mtl
+o Cube
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+usemtl Material
+s off
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9/3 8/10/3 6/11/3 5/12/3
+f 5/13/4 6/14/4 2/15/4 1/16/4
+f 3/5/5 7/17/5 5/18/5 1/16/5
+f 8/19/6 4/6/6 2/15/6 6/20/6
diff --git a/specs/data/box-diffuse-ambient-same/cesium.png b/specs/data/box-diffuse-ambient-same/cesium.png
new file mode 100644
index 0000000..3b8baee
Binary files /dev/null and b/specs/data/box-diffuse-ambient-same/cesium.png differ
diff --git a/specs/data/box-external-resources-in-root/box-external-resources-in-root.mtl b/specs/data/box-external-resources-in-root/box-external-resources-in-root.mtl
new file mode 100644
index 0000000..2e2d3a5
--- /dev/null
+++ b/specs/data/box-external-resources-in-root/box-external-resources-in-root.mtl
@@ -0,0 +1,13 @@
+# Blender MTL File: 'box.blend'
+# Material Count: 1
+
+newmtl MaterialTextured
+Ns 96.078431
+Ka 0.000000 0.000000 0.000000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+map_Kd ../box-textured/cesium.png
diff --git a/specs/data/box-external-resources-in-root/box-external-resources-in-root.obj b/specs/data/box-external-resources-in-root/box-external-resources-in-root.obj
new file mode 100644
index 0000000..6b17fc5
--- /dev/null
+++ b/specs/data/box-external-resources-in-root/box-external-resources-in-root.obj
@@ -0,0 +1,46 @@
+# Blender v2.78 (sub 0) OBJ File: 'box-multiple-materials.blend'
+# www.blender.org
+mtllib box-external-resources-in-root.mtl
+mtllib ../box/box.mtl
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+vn -1.0000 0.0000 0.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 0.0000 0.0000 1.0000
+usemtl MaterialTextured
+f 3/1/1 7/2/1 5/3/1 1/4/1
+f 1/9/3 2/10/3 4/11/3 3/12/3
+f 3/1/5 4/6/5 8/17/5 7/18/5
+usemtl Material
+f 8/5/2 4/6/2 2/7/2 6/8/2
+f 7/13/4 8/14/4 6/15/4 5/16/4
+f 5/19/6 6/20/6 2/7/6 1/4/6
diff --git a/specs/data/box-external-resources-in-root/box.mtl b/specs/data/box-external-resources-in-root/box.mtl
new file mode 100644
index 0000000..4f8d129
--- /dev/null
+++ b/specs/data/box-external-resources-in-root/box.mtl
@@ -0,0 +1,12 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl Material
+Ns 96.078431
+Ka 0.100000 0.000000 0.000000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.100000
+Ni 1.000000
+d 1.000000
+illum 2
diff --git a/specs/data/box-external-resources-in-root/cesium.png b/specs/data/box-external-resources-in-root/cesium.png
new file mode 100644
index 0000000..3b8baee
Binary files /dev/null and b/specs/data/box-external-resources-in-root/cesium.png differ
diff --git a/specs/data/box-missing-usemtl/box-missing-usemtl.mtl b/specs/data/box-missing-usemtl/box-missing-usemtl.mtl
new file mode 100644
index 0000000..4f8d129
--- /dev/null
+++ b/specs/data/box-missing-usemtl/box-missing-usemtl.mtl
@@ -0,0 +1,12 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl Material
+Ns 96.078431
+Ka 0.100000 0.000000 0.000000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.100000
+Ni 1.000000
+d 1.000000
+illum 2
diff --git a/specs/data/box-missing-usemtl/box-missing-usemtl.obj b/specs/data/box-missing-usemtl/box-missing-usemtl.obj
new file mode 100644
index 0000000..4fc5eee
--- /dev/null
+++ b/specs/data/box-missing-usemtl/box-missing-usemtl.obj
@@ -0,0 +1,45 @@
+# Blender v2.78 (sub 0) OBJ File: ''
+# www.blender.org
+mtllib box-missing-usemtl.mtl
+o Cube
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+s off
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9/3 8/10/3 6/11/3 5/12/3
+f 5/13/4 6/14/4 2/15/4 1/16/4
+f 3/5/5 7/17/5 5/18/5 1/16/5
+f 8/19/6 4/6/6 2/15/6 6/20/6
diff --git a/specs/data/box-mixed-attributes-2/box-mixed-attributes-2.mtl b/specs/data/box-mixed-attributes-2/box-mixed-attributes-2.mtl
new file mode 100644
index 0000000..d81606d
--- /dev/null
+++ b/specs/data/box-mixed-attributes-2/box-mixed-attributes-2.mtl
@@ -0,0 +1,13 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl Material
+Ns 96.078431
+Ka 0.100000 0.000000 0.000000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.100000
+Ni 1.000000
+d 1.000000
+illum 2
+map_Kd cesium.png
diff --git a/specs/data/box-mixed-attributes-2/box-mixed-attributes-2.obj b/specs/data/box-mixed-attributes-2/box-mixed-attributes-2.obj
new file mode 100644
index 0000000..2762b61
--- /dev/null
+++ b/specs/data/box-mixed-attributes-2/box-mixed-attributes-2.obj
@@ -0,0 +1,67 @@
+# Blender v2.78 (sub 0) OBJ File: ''
+# www.blender.org
+mtllib box-mixed-attributes-2.mtl
+o Cube
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+# Using default material
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9 8/10 6/11 5/12
+f 5/13 6/14 2/15 1/16
+f 3//5 7//5 5//5 1//5
+f 8//6 4//6 2//6 6//6
+usemtl Material
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9 8/10 6/11 5/12
+f 5/13 6/14 2/15 1/16
+f 3//5 7//5 5//5 1//5
+f 8//6 4//6 2//6 6//6
+usemtl Missing
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9 8/10 6/11 5/12
+f 5/13 6/14 2/15 1/16
+f 3//5 7//5 5//5 1//5
+f 8//6 4//6 2//6 6//6
+o CubeCopy
+usemtl Material
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9 8/10 6/11 5/12
+f 5/13 6/14 2/15 1/16
+f 3//5 7//5 5//5 1//5
+f 8//6 4//6 2//6 6//6
diff --git a/specs/data/box-mixed-attributes-2/cesium.png b/specs/data/box-mixed-attributes-2/cesium.png
new file mode 100644
index 0000000..3b8baee
Binary files /dev/null and b/specs/data/box-mixed-attributes-2/cesium.png differ
diff --git a/specs/data/box-mtllib-spaces/box mtllib blue.mtl b/specs/data/box-mtllib-spaces/box mtllib blue.mtl
new file mode 100644
index 0000000..d3fe863
--- /dev/null
+++ b/specs/data/box-mtllib-spaces/box mtllib blue.mtl	
@@ -0,0 +1,12 @@
+# Blender MTL File: 'box-multiple-materials.blend'
+# Material Count: 1
+
+newmtl Blue
+Ns 96.078431
+Ka 0.000000 0.000000 0.000000
+Kd 0.000000 0.000000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
diff --git a/specs/data/box-mtllib-spaces/box mtllib green.mtl b/specs/data/box-mtllib-spaces/box mtllib green.mtl
new file mode 100644
index 0000000..89abba9
--- /dev/null
+++ b/specs/data/box-mtllib-spaces/box mtllib green.mtl	
@@ -0,0 +1,12 @@
+# Blender MTL File: 'box-multiple-materials.blend'
+# Material Count: 1
+
+newmtl Green
+Ns 96.078431
+Ka 0.000000 0.000000 0.000000
+Kd 0.000000 0.640000 0.000000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
diff --git a/specs/data/box-mtllib-spaces/box mtllib red.mtl b/specs/data/box-mtllib-spaces/box mtllib red.mtl
new file mode 100644
index 0000000..3721d86
--- /dev/null
+++ b/specs/data/box-mtllib-spaces/box mtllib red.mtl	
@@ -0,0 +1,12 @@
+# Blender MTL File: 'box-multiple-materials.blend'
+# Material Count: 1
+
+newmtl Red
+Ns 96.078431
+Ka 0.000000 0.000000 0.000000
+Kd 0.640000 0.000000 0.000000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
diff --git a/specs/data/box-mtllib-spaces/box mtllib.obj b/specs/data/box-mtllib-spaces/box mtllib.obj
new file mode 100644
index 0000000..fe03d89
--- /dev/null
+++ b/specs/data/box-mtllib-spaces/box mtllib.obj	
@@ -0,0 +1,50 @@
+# Blender v2.78 (sub 0) OBJ File: 'box-multiple-materials.blend'
+# www.blender.org
+mtllib box mtllib red.mtl
+mtllib box mtllib green.mtl box mtllib blue.mtl 
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+vn -1.0000 0.0000 0.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 0.0000 0.0000 1.0000
+usemtl Red
+f 3/1/1 7/2/1 5/3/1 1/4/1
+usemtl Green
+f 1/9/3 2/10/3 4/11/3 3/12/3
+usemtl Blue
+f 3/1/5 4/6/5 8/17/5 7/18/5
+usemtl Red
+f 8/5/2 4/6/2 2/7/2 6/8/2
+usemtl Green
+f 7/13/4 8/14/4 6/15/4 5/16/4
+usemtl Blue
+f 5/19/6 6/20/6 2/7/6 1/4/6
diff --git a/specs/data/box-objects-groups-materials-2/box-objects-groups-materials-2.mtl b/specs/data/box-objects-groups-materials-2/box-objects-groups-materials-2.mtl
new file mode 100644
index 0000000..2f9b11a
--- /dev/null
+++ b/specs/data/box-objects-groups-materials-2/box-objects-groups-materials-2.mtl
@@ -0,0 +1,32 @@
+# Blender MTL File: 'box-objects.blend'
+# Material Count: 3
+
+newmtl Blue
+Ns 96.078431
+Ka 0.000000 0.000000 0.000000
+Kd 0.000000 0.000000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl Green
+Ns 96.078431
+Ka 0.000000 0.000000 0.000000
+Kd 0.000000 0.640000 0.000000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+
+newmtl Red
+Ns 96.078431
+Ka 0.000000 0.000000 0.000000
+Kd 0.640000 0.000000 0.000000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
diff --git a/specs/data/box-objects-groups-materials-2/box-objects-groups-materials-2.obj b/specs/data/box-objects-groups-materials-2/box-objects-groups-materials-2.obj
new file mode 100644
index 0000000..aed6a84
--- /dev/null
+++ b/specs/data/box-objects-groups-materials-2/box-objects-groups-materials-2.obj
@@ -0,0 +1,133 @@
+# Blender v2.78 (sub 0) OBJ File: 'box-objects.blend'
+# www.blender.org
+mtllib box-objects-groups-materials-2.mtl
+usemtl Blue
+o Cube
+v -1.000000 -1.000000 -4.000000
+v -1.000000 1.000000 -4.000000
+v -1.000000 -1.000000 -6.000000
+v -1.000000 1.000000 -6.000000
+v 1.000000 -1.000000 -4.000000
+v 1.000000 1.000000 -4.000000
+v 1.000000 -1.000000 -6.000000
+v 1.000000 1.000000 -6.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+g Blue
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9/3 8/10/3 6/11/3 5/12/3
+usemtl Green
+f 5/13/4 6/14/4 2/15/4 1/16/4
+f 3/5/5 7/17/5 5/18/5 1/16/5
+f 8/19/6 4/6/6 2/15/6 6/20/6
+v 4.000000 -1.000000 1.000000
+v 4.000000 1.000000 1.000000
+v 4.000000 -1.000000 -1.000000
+v 4.000000 1.000000 -1.000000
+v 6.000000 -1.000000 1.000000
+v 6.000000 1.000000 1.000000
+v 6.000000 -1.000000 -1.000000
+v 6.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+usemtl Green
+g Green
+f 9/21/7 10/22/7 12/23/7 11/24/7
+f 11/25/8 12/26/8 16/27/8 15/28/8
+f 15/29/9 16/30/9 14/31/9 13/32/9
+usemtl Red
+f 13/33/10 14/34/10 10/35/10 9/36/10
+f 11/25/11 15/37/11 13/38/11 9/36/11
+f 16/39/12 12/26/12 10/35/12 14/40/12
+usemtl Red
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+g Red
+f 21/53/16 22/54/16 18/55/16 17/56/16
+f 19/45/17 23/57/17 21/58/17 17/56/17
+f 24/59/18 20/46/18 18/55/18 22/60/18
+usemtl Blue
+f 17/41/13 18/42/13 20/43/13 19/44/13
+f 19/45/14 20/46/14 24/47/14 23/48/14
+f 23/49/15 24/50/15 22/51/15 21/52/15
diff --git a/specs/data/box-objects-groups-materials/box-objects-groups-materials.obj b/specs/data/box-objects-groups-materials/box-objects-groups-materials.obj
index 1bb7698..b2fb821 100644
--- a/specs/data/box-objects-groups-materials/box-objects-groups-materials.obj
+++ b/specs/data/box-objects-groups-materials/box-objects-groups-materials.obj
@@ -36,7 +36,7 @@ vn 1.0000 0.0000 0.0000
 vn 0.0000 0.0000 1.0000
 vn 0.0000 -1.0000 0.0000
 vn 0.0000 1.0000 0.0000
-g CubeBlue_CubeBlue_Blue
+g Blue
 usemtl Blue
 f 1/1/1 2/2/1 4/3/1 3/4/1
 f 3/5/2 4/6/2 8/7/2 7/8/2
@@ -79,7 +79,7 @@ vn 1.0000 0.0000 0.0000
 vn 0.0000 0.0000 1.0000
 vn 0.0000 -1.0000 0.0000
 vn 0.0000 1.0000 0.0000
-g CubeGreen_CubeGreen_Green
+g Green
 usemtl Green
 f 9/21/7 10/22/7 12/23/7 11/24/7
 f 11/25/8 12/26/8 16/27/8 15/28/8
@@ -122,7 +122,7 @@ vn 1.0000 0.0000 0.0000
 vn 0.0000 0.0000 1.0000
 vn 0.0000 -1.0000 0.0000
 vn 0.0000 1.0000 0.0000
-g CubeRed_CubeRed_Red
+g Red
 usemtl Red
 f 17/41/13 18/42/13 20/43/13 19/44/13
 f 19/45/14 20/46/14 24/47/14 23/48/14
diff --git a/specs/data/box-resources-in-root/box-resources-in-root.mtl b/specs/data/box-resources-in-root/box-resources-in-root.mtl
new file mode 100644
index 0000000..7bc1846
--- /dev/null
+++ b/specs/data/box-resources-in-root/box-resources-in-root.mtl
@@ -0,0 +1,13 @@
+# Blender MTL File: 'box.blend'
+# Material Count: 1
+
+newmtl Material
+Ns 96.078431
+Ka 0.000000 0.000000 0.000000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.000000
+d 1.000000
+illum 2
+map_Kd resources/textures/cesium.png
diff --git a/specs/data/box-resources-in-root/box-resources-in-root.obj b/specs/data/box-resources-in-root/box-resources-in-root.obj
new file mode 100644
index 0000000..1e9d945
--- /dev/null
+++ b/specs/data/box-resources-in-root/box-resources-in-root.obj
@@ -0,0 +1,46 @@
+# Blender v2.78 (sub 0) OBJ File: 'box.blend'
+# www.blender.org
+mtllib resources/box-resources-in-root.mtl
+o Cube
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+usemtl Material
+s off
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9/3 8/10/3 6/11/3 5/12/3
+f 5/13/4 6/14/4 2/15/4 1/16/4
+f 3/5/5 7/17/5 5/18/5 1/16/5
+f 8/19/6 4/6/6 2/15/6 6/20/6
diff --git a/specs/data/box-resources-in-root/cesium.png b/specs/data/box-resources-in-root/cesium.png
new file mode 100644
index 0000000..3b8baee
Binary files /dev/null and b/specs/data/box-resources-in-root/cesium.png differ
diff --git a/specs/data/box-texture-options/ambient.gif b/specs/data/box-texture-options/ambient.gif
new file mode 100644
index 0000000..1276823
Binary files /dev/null and b/specs/data/box-texture-options/ambient.gif differ
diff --git a/specs/data/box-texture-options/box-texture-options.mtl b/specs/data/box-texture-options/box-texture-options.mtl
new file mode 100644
index 0000000..3434533
--- /dev/null
+++ b/specs/data/box-texture-options/box-texture-options.mtl
@@ -0,0 +1,19 @@
+# Blender MTL File: 'box.blend'
+# Material Count: 1
+
+newmtl Material
+Ns 96.078431
+Ka 0.200000 0.200000 0.200000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.100000 0.100000 0.100000
+Ni 1.000000
+d 0.900000
+Tr 0.100000
+map_Ka -s 1.0 1.0 1.0 -o 0.0 0.0 0.0 ambient.gif
+map_Ke -s 1.0 1.0 1.0 -o 0.0 0.0 0.0 emission.jpg
+map_Kd -s 1.0 1.0 1.0 -o 0.0 0.0 0.0 diffuse.png
+map_Ks -s 1.0 1.0 1.0 -o 0.0 0.0 0.0 specular.jpeg
+map_Ns -s 1.0 1.0 1.0 -o 0.0 0.0 0.0 shininess.png
+map_Bump -bm 0.2 bump.png
+illum 2
diff --git a/specs/data/box-texture-options/box-texture-options.obj b/specs/data/box-texture-options/box-texture-options.obj
new file mode 100644
index 0000000..3207f00
--- /dev/null
+++ b/specs/data/box-texture-options/box-texture-options.obj
@@ -0,0 +1,46 @@
+# Blender v2.78 (sub 0) OBJ File: 'box.blend'
+# www.blender.org
+mtllib box-texture-options.mtl
+o Cube
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+usemtl Material
+s off
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9/3 8/10/3 6/11/3 5/12/3
+f 5/13/4 6/14/4 2/15/4 1/16/4
+f 3/5/5 7/17/5 5/18/5 1/16/5
+f 8/19/6 4/6/6 2/15/6 6/20/6
diff --git a/specs/data/box-texture-options/bump.png b/specs/data/box-texture-options/bump.png
new file mode 100644
index 0000000..16ec3a9
Binary files /dev/null and b/specs/data/box-texture-options/bump.png differ
diff --git a/specs/data/box-texture-options/diffuse.png b/specs/data/box-texture-options/diffuse.png
new file mode 100644
index 0000000..8704966
Binary files /dev/null and b/specs/data/box-texture-options/diffuse.png differ
diff --git a/specs/data/box-texture-options/emission.jpg b/specs/data/box-texture-options/emission.jpg
new file mode 100644
index 0000000..e5c85a9
Binary files /dev/null and b/specs/data/box-texture-options/emission.jpg differ
diff --git a/specs/data/box-texture-options/shininess.png b/specs/data/box-texture-options/shininess.png
new file mode 100644
index 0000000..bfcf1a2
Binary files /dev/null and b/specs/data/box-texture-options/shininess.png differ
diff --git a/specs/data/box-texture-options/specular.jpeg b/specs/data/box-texture-options/specular.jpeg
new file mode 100644
index 0000000..661bf98
Binary files /dev/null and b/specs/data/box-texture-options/specular.jpeg differ
diff --git a/specs/data/box-unnormalized/box-unnormalized.mtl b/specs/data/box-unnormalized/box-unnormalized.mtl
new file mode 100644
index 0000000..4f8d129
--- /dev/null
+++ b/specs/data/box-unnormalized/box-unnormalized.mtl
@@ -0,0 +1,12 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl Material
+Ns 96.078431
+Ka 0.100000 0.000000 0.000000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.100000
+Ni 1.000000
+d 1.000000
+illum 2
diff --git a/specs/data/box-unnormalized/box-unnormalized.obj b/specs/data/box-unnormalized/box-unnormalized.obj
new file mode 100644
index 0000000..f52251e
--- /dev/null
+++ b/specs/data/box-unnormalized/box-unnormalized.obj
@@ -0,0 +1,46 @@
+# Blender v2.78 (sub 0) OBJ File: ''
+# www.blender.org
+mtllib box-unnormalized.mtl
+o Cube
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn 0.0000 0.0000 0.0000
+vn 0.0000 0.0000 0.5
+vn 1.0000 0.1000 0.0000
+vn 0.0000 0.0000 -0.9
+vn 0.0000 1.0000 0.0000
+vn 10.0000 -10.0000 5.0000
+usemtl Material
+s off
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/5/2 4/6/2 8/7/2 7/8/2
+f 7/9/3 8/10/3 6/11/3 5/12/3
+f 5/13/4 6/14/4 2/15/4 1/16/4
+f 3/5/5 7/17/5 5/18/5 1/16/5
+f 8/19/6 4/6/6 2/15/6 6/20/6
diff --git a/specs/data/box/box.mtl b/specs/data/box/box.mtl
index a304b43..4f8d129 100644
--- a/specs/data/box/box.mtl
+++ b/specs/data/box/box.mtl
@@ -3,10 +3,10 @@
 
 newmtl Material
 Ns 96.078431
-Ka 0.000000 0.000000 0.000000
+Ka 0.100000 0.000000 0.000000
 Kd 0.640000 0.640000 0.640000
 Ks 0.500000 0.500000 0.500000
-Ke 0.000000 0.000000 0.000000
+Ke 0.000000 0.000000 0.100000
 Ni 1.000000
 d 1.000000
 illum 2
diff --git a/specs/lib/createGltfSpec.js b/specs/lib/createGltfSpec.js
index 87ea212..329d12f 100644
--- a/specs/lib/createGltfSpec.js
+++ b/specs/lib/createGltfSpec.js
@@ -8,10 +8,12 @@ var loadObj = require('../../lib/loadObj');
 var Material = require('../../lib/Material');
 
 var clone = Cesium.clone;
+var defined = Cesium.defined;
 var WebGLConstants = Cesium.WebGLConstants;
 
 var boxObjUrl = 'specs/data/box/box.obj';
 var groupObjUrl = 'specs/data/box-objects-groups-materials/box-objects-groups-materials.obj';
+var mixedAttributesObjUrl = 'specs/data/box-mixed-attributes-2/box-mixed-attributes-2.obj';
 var diffuseTextureUrl = 'specs/data/box-textured/cesium.png';
 var transparentDiffuseTextureUrl = 'specs/data/box-complex-material/diffuse.png';
 
@@ -23,6 +25,7 @@ describe('createGltf', function() {
     var boxObjData;
     var duplicateBoxObjData;
     var groupObjData;
+    var mixedAttributesObjData;
     var diffuseTexture;
     var transparentDiffuseTexture;
 
@@ -40,6 +43,10 @@ describe('createGltf', function() {
                 .then(function(data) {
                     groupObjData = data;
                 }),
+            loadObj(mixedAttributesObjUrl, defaultOptions)
+                .then(function(data) {
+                    mixedAttributesObjData = data;
+                }),
             loadImage(diffuseTextureUrl, defaultOptions)
                 .then(function(image) {
                     diffuseTexture = image;
@@ -258,8 +265,8 @@ describe('createGltf', function() {
         boxObjData.nodes[1].meshes[0].primitives[0].normals.length = 0;
 
         var gltf = createGltf(boxObjData, defaultOptions);
-        var kmc1 = gltf.materials.Material.extensions.KHR_materials_common;
-        var kmc2 = gltf.materials.Material_constant.extensions.KHR_materials_common;
+        var kmc1 = gltf.materials['Material'].extensions.KHR_materials_common;
+        var kmc2 = gltf.materials['Material-2'].extensions.KHR_materials_common;
 
         expect(kmc1.technique).toBe('PHONG');
         expect(kmc2.technique).toBe('CONSTANT');
@@ -271,8 +278,8 @@ describe('createGltf', function() {
         boxObjData.nodes[0].meshes[0].primitives[0].normals.length = 0;
 
         var gltf = createGltf(boxObjData, defaultOptions);
-        var kmc1 = gltf.materials.Material.extensions.KHR_materials_common;
-        var kmc2 = gltf.materials.Material_shaded.extensions.KHR_materials_common;
+        var kmc1 = gltf.materials['Material'].extensions.KHR_materials_common;
+        var kmc2 = gltf.materials['Material-2'].extensions.KHR_materials_common;
 
         expect(kmc1.technique).toBe('CONSTANT');
         expect(kmc2.technique).toBe('PHONG');
@@ -309,6 +316,57 @@ describe('createGltf', function() {
         expect(attributes.TEXCOORD_0).toBeUndefined();
     });
 
+    function getMaterialValue(material, property) {
+        return material.extensions.KHR_materials_common.values[property];
+    }
+
+    it('splits incompatible materials', function() {
+        var gltf = createGltf(mixedAttributesObjData, defaultOptions);
+        var meshes = gltf.meshes;
+        var materials = gltf.materials;
+        var materialNames = Object.keys(materials).sort();
+
+        // Expect three copies of each material for
+        // * positions/normals/uvs
+        // * positions/normals
+        // * positions/uvs
+        expect(materialNames).toEqual([
+            'Material',
+            'Material-2',
+            'Material-3',
+            'Missing',
+            'Missing-2',
+            'Missing-3',
+            'default',
+            'default-2',
+            'default-3'
+        ]);
+
+        expect(getMaterialValue(materials['Material'], 'diffuse')).toBe('texture_cesium');
+        expect(getMaterialValue(materials['Material'], 'emission')).toEqual([0.0, 0.0, 0.1, 1.0]);
+        expect(getMaterialValue(materials['Material-2'], 'diffuse')).toEqual([0.0, 0.0, 0.0, 1.0]);
+        expect(getMaterialValue(materials['Material-2'], 'emission')).toBe('texture_cesium');
+        expect(getMaterialValue(materials['Material-3'], 'diffuse')).toEqual([0.64, 0.64, 0.64, 1.0]);
+        expect(getMaterialValue(materials['Material-3'], 'emission')).toEqual([0.0, 0.0, 0.1, 1.0]);
+
+        // Test that primitives without uvs reference materials without textures
+        for (var meshName in meshes) {
+            if (meshes.hasOwnProperty(meshName)) {
+                var mesh = meshes[meshName];
+                var primitives = mesh.primitives;
+                var primitivesLength = primitives.length;
+                for (var i = 0; i < primitivesLength; ++i) {
+                    var primitive = primitives[i];
+                    var material = materials[primitive.material];
+                    if (!defined(primitive.attributes.TEXCOORD_0)) {
+                        expect(typeof getMaterialValue(material, 'diffuse') === 'string').toBe(false);
+                        expect(typeof getMaterialValue(material, 'emission') === 'string').toBe(false);
+                    }
+                }
+            }
+        }
+    });
+
     function expandObjData(objData, duplicatesLength) {
         var primitive = objData.nodes[0].meshes[0].primitives[0];
         var indices = primitive.indices;
diff --git a/specs/lib/loadMtlSpec.js b/specs/lib/loadMtlSpec.js
index 53fc226..ae579d1 100644
--- a/specs/lib/loadMtlSpec.js
+++ b/specs/lib/loadMtlSpec.js
@@ -2,8 +2,10 @@
 var path = require('path');
 var loadMtl = require('../../lib/loadMtl');
 
-var complexMaterialUrl = 'specs/data/box-complex-material/box-complex-material.mtl';
+var complexMaterialAlphaUrl = 'specs/data/box-complex-material-alpha/box-complex-material-alpha.mtl';
+var diffuseAmbientSameMaterialUrl = 'specs/data/box-diffuse-ambient-same/box-diffuse-ambient-same.mtl';
 var multipleMaterialsUrl = 'specs/data/box-multiple-materials/box-multiple-materials.mtl';
+var texturedWithOptionsMaterialUrl = 'specs/data/box-texture-options/box-texture-options.mtl';
 var transparentMaterialUrl = 'specs/data/box-transparent/box-transparent.mtl';
 
 function getImagePath(objPath, relativePath) {
@@ -12,7 +14,7 @@ function getImagePath(objPath, relativePath) {
 
 describe('loadMtl', function() {
     it('loads complex material', function(done) {
-        expect(loadMtl(complexMaterialUrl)
+        expect(loadMtl(complexMaterialAlphaUrl)
             .then(function(materials) {
                 var material = materials.Material;
                 expect(material).toBeDefined();
@@ -22,13 +24,13 @@ describe('loadMtl', function() {
                 expect(material.specularColor).toEqual([0.5, 0.5, 0.5, 1.0]);
                 expect(material.specularShininess).toEqual(96.078431);
                 expect(material.alpha).toEqual(0.9);
-                expect(material.ambientTexture).toEqual(getImagePath(complexMaterialUrl, 'ambient.gif'));
-                expect(material.emissionTexture).toEqual(getImagePath(complexMaterialUrl, 'emission.jpg'));
-                expect(material.diffuseTexture).toEqual(getImagePath(complexMaterialUrl, 'diffuse.png'));
-                expect(material.specularTexture).toEqual(getImagePath(complexMaterialUrl, 'specular.jpeg'));
-                expect(material.specularShininessMap).toEqual(getImagePath(complexMaterialUrl, 'shininess.png'));
-                expect(material.normalMap).toEqual(getImagePath(complexMaterialUrl, 'bump.png'));
-                expect(material.alphaMap).toEqual(getImagePath(complexMaterialUrl, 'alpha.png'));
+                expect(material.ambientTexture).toEqual(getImagePath(complexMaterialAlphaUrl, 'ambient.gif'));
+                expect(material.emissionTexture).toEqual(getImagePath(complexMaterialAlphaUrl, 'emission.jpg'));
+                expect(material.diffuseTexture).toEqual(getImagePath(complexMaterialAlphaUrl, 'diffuse.png'));
+                expect(material.specularTexture).toEqual(getImagePath(complexMaterialAlphaUrl, 'specular.jpeg'));
+                expect(material.specularShininessMap).toEqual(getImagePath(complexMaterialAlphaUrl, 'shininess.png'));
+                expect(material.normalMap).toEqual(getImagePath(complexMaterialAlphaUrl, 'bump.png'));
+                expect(material.alphaMap).toEqual(getImagePath(complexMaterialAlphaUrl, 'alpha.png'));
             }), done).toResolve();
     });
 
@@ -42,6 +44,36 @@ describe('loadMtl', function() {
             }), done).toResolve();
     });
 
+    it('loads mtl with textures having options', function(done) {
+        expect(loadMtl(texturedWithOptionsMaterialUrl)
+            .then(function(materials) {
+                var material = materials.Material;
+                expect(material).toBeDefined();
+                expect(material.ambientColor).toEqual([0.2, 0.2, 0.2, 1.0]);
+                expect(material.emissionColor).toEqual([0.1, 0.1, 0.1, 1.0]);
+                expect(material.diffuseColor).toEqual([0.64, 0.64, 0.64, 1.0]);
+                expect(material.specularColor).toEqual([0.5, 0.5, 0.5, 1.0]);
+                expect(material.specularShininess).toEqual(96.078431);
+                expect(material.alpha).toEqual(0.9);
+                expect(material.ambientTexture).toEqual(getImagePath(texturedWithOptionsMaterialUrl, 'ambient.gif'));
+                expect(material.emissionTexture).toEqual(getImagePath(texturedWithOptionsMaterialUrl, 'emission.jpg'));
+                expect(material.diffuseTexture).toEqual(getImagePath(texturedWithOptionsMaterialUrl, 'diffuse.png'));
+                expect(material.specularTexture).toEqual(getImagePath(texturedWithOptionsMaterialUrl, 'specular.jpeg'));
+                expect(material.specularShininessMap).toEqual(getImagePath(texturedWithOptionsMaterialUrl, 'shininess.png'));
+                expect(material.normalMap).toEqual(getImagePath(texturedWithOptionsMaterialUrl, 'bump.png'));
+            }), done).toResolve();
+    });
+
+    it('ambient texture is ignored if it is the same as the diffuse texture', function(done) {
+        expect(loadMtl(diffuseAmbientSameMaterialUrl)
+            .then(function(materials) {
+                expect(Object.keys(materials).length).toBe(1);
+                var material = materials['Material'];
+                expect(material.diffuseTexture).toBeDefined();
+                expect(material.ambientTexture).toBeUndefined();
+            }), done).toResolve();
+    });
+
     it('alpha of 0.0 is treated as 1.0', function(done) {
         expect(loadMtl(transparentMaterialUrl)
             .then(function(materials) {
diff --git a/specs/lib/loadObjSpec.js b/specs/lib/loadObjSpec.js
index f635878..7d3bc0d 100644
--- a/specs/lib/loadObjSpec.js
+++ b/specs/lib/loadObjSpec.js
@@ -7,6 +7,7 @@ var obj2gltf = require('../../lib/obj2gltf');
 
 var Cartesian3 = Cesium.Cartesian3;
 var clone = Cesium.clone;
+var CesiumMath = Cesium.Math;
 var RuntimeError = Cesium.RuntimeError;
 
 var objUrl = 'specs/data/box/box.obj';
@@ -19,14 +20,21 @@ var objTrianglesUrl = 'specs/data/box-triangles/box-triangles.obj';
 var objObjectsUrl = 'specs/data/box-objects/box-objects.obj';
 var objGroupsUrl = 'specs/data/box-groups/box-groups.obj';
 var objObjectsGroupsUrl = 'specs/data/box-objects-groups/box-objects-groups.obj';
+var objObjectsGroupsMaterialsUrl = 'specs/data/box-objects-groups-materials/box-objects-groups-materials.obj';
+var objObjectsGroupsMaterials2Url = 'specs/data/box-objects-groups-materials-2/box-objects-groups-materials-2.obj';
 var objConcaveUrl = 'specs/data/concave/concave.obj';
+var objUnnormalizedUrl = 'specs/data/box-unnormalized/box-unnormalized.obj';
 var objUsemtlUrl = 'specs/data/box-usemtl/box-usemtl.obj';
 var objNoMaterialsUrl = 'specs/data/box-no-materials/box-no-materials.obj';
 var objMultipleMaterialsUrl = 'specs/data/box-multiple-materials/box-multiple-materials.obj';
 var objUncleanedUrl = 'specs/data/box-uncleaned/box-uncleaned.obj';
 var objMtllibUrl = 'specs/data/box-mtllib/box-mtllib.obj';
+var objMtllibSpacesUrl = 'specs/data/box-mtllib-spaces/box mtllib.obj';
 var objMissingMtllibUrl = 'specs/data/box-missing-mtllib/box-missing-mtllib.obj';
+var objMissingUsemtlUrl = 'specs/data/box-missing-usemtl/box-missing-usemtl.obj';
 var objExternalResourcesUrl = 'specs/data/box-external-resources/box-external-resources.obj';
+var objResourcesInRootUrl = 'specs/data/box-resources-in-root/box-resources-in-root.obj';
+var objExternalResourcesInRootUrl = 'specs/data/box-external-resources-in-root/box-external-resources-in-root.obj';
 var objTexturedUrl = 'specs/data/box-textured/box-textured.obj';
 var objMissingTextureUrl = 'specs/data/box-missing-texture/box-missing-texture.obj';
 var objSubdirectoriesUrl = 'specs/data/box-subdirectories/box-textured.obj';
@@ -110,6 +118,23 @@ describe('loadObj', function() {
             }), done).toResolve();
     });
 
+    it('normalizes normals', function(done) {
+        expect(loadObj(objUnnormalizedUrl, defaultOptions)
+            .then(function(data) {
+                var scratchNormal = new Cesium.Cartesian3();
+                var primitive = getPrimitives(data)[0];
+                var normals = primitive.normals;
+                var normalsLength = normals.length / 3;
+                for (var i = 0; i < normalsLength; ++i) {
+                    var normalX = normals.get(i * 3);
+                    var normalY = normals.get(i * 3 + 1);
+                    var normalZ = normals.get(i * 3 + 2);
+                    var normal = Cartesian3.fromElements(normalX, normalY, normalZ, scratchNormal);
+                    expect(Cartesian3.magnitude(normal)).toEqualEpsilon(1.0, CesiumMath.EPSILON5);
+                }
+            }), done).toResolve();
+    });
+
     it('loads obj with uvs', function(done) {
         expect(loadObj(objUvsUrl, defaultOptions)
             .then(function(data) {
@@ -198,6 +223,41 @@ describe('loadObj', function() {
             }), done).toResolve();
     });
 
+    function loadsObjWithObjectsGroupsAndMaterials(data) {
+        var nodes = data.nodes;
+        expect(nodes.length).toBe(1);
+        expect(nodes[0].name).toBe('Cube');
+        var meshes = getMeshes(data);
+        expect(meshes.length).toBe(3);
+        expect(meshes[0].name).toBe('Blue');
+        expect(meshes[1].name).toBe('Green');
+        expect(meshes[2].name).toBe('Red');
+        var primitives = getPrimitives(data);
+        expect(primitives.length).toBe(6);
+        expect(primitives[0].material).toBe('Blue');
+        expect(primitives[1].material).toBe('Green');
+        expect(primitives[2].material).toBe('Green');
+        expect(primitives[3].material).toBe('Red');
+        expect(primitives[4].material).toBe('Red');
+        expect(primitives[5].material).toBe('Blue');
+    }
+
+    it('loads obj with objects, groups, and materials', function(done) {
+        expect(loadObj(objObjectsGroupsMaterialsUrl, defaultOptions)
+            .then(function(data) {
+                loadsObjWithObjectsGroupsAndMaterials(data);
+            }), done).toResolve();
+    });
+
+    it('loads obj with objects, groups, and materials (2)', function(done) {
+        // The usemtl lines are placed in an unordered fashion but
+        // should produce the same result as the previous test
+        expect(loadObj(objObjectsGroupsMaterials2Url, defaultOptions)
+            .then(function(data) {
+                loadsObjWithObjectsGroupsAndMaterials(data);
+            }), done).toResolve();
+    });
+
     it('loads obj with concave face containing 5 vertices', function(done) {
         expect(loadObj(objConcaveUrl, defaultOptions)
             .then(function(data) {
@@ -293,11 +353,37 @@ describe('loadObj', function() {
             }), done).toResolve();
     });
 
+    it('loads obj with mtllib paths with spaces', function(done) {
+        expect(loadObj(objMtllibSpacesUrl, defaultOptions)
+            .then(function(data) {
+                var materials = data.materials;
+                expect(Object.keys(materials).length).toBe(3);
+                expect(materials['Blue'].diffuseColor).toEqual([0.0, 0.0, 0.64, 1.0]);
+                expect(materials['Green'].diffuseColor).toEqual([0.0, 0.64, 0.0, 1.0]);
+                expect(materials['Red'].diffuseColor).toEqual([0.64, 0.0, 0.0, 1.0]);
+            }), done).toResolve();
+    });
+
     it('loads obj with missing mtllib', function(done) {
-        expect(loadObj(objMissingMtllibUrl, defaultOptions)
+        var options = clone(defaultOptions);
+        var spy = jasmine.createSpy('logger');
+        options.logger = spy;
+
+        expect(loadObj(objMissingMtllibUrl, options)
             .then(function(data) {
                 expect(data.materials).toEqual({});
-                expect(console.log.calls.argsFor(0)[0].indexOf('Could not read mtl file') >= 0).toBe(true);
+                expect(spy.calls.argsFor(0)[0].indexOf('ENOENT') >= 0).toBe(true);
+                expect(spy.calls.argsFor(1)[0].indexOf('Attempting to read the material file from within the obj directory instead.') >= 0).toBe(true);
+                expect(spy.calls.argsFor(2)[0].indexOf('ENOENT') >= 0).toBe(true);
+                expect(spy.calls.argsFor(3)[0].indexOf('Could not read material file') >= 0).toBe(true);
+            }), done).toResolve();
+    });
+
+    it('loads obj with missing usemtl', function(done) {
+        expect(loadObj(objMissingUsemtlUrl, defaultOptions)
+            .then(function(data) {
+                expect(Object.keys(data.materials).length).toBe(1);
+                expect(data.nodes[0].meshes[0].primitives[0].material).toBe('Material');
             }), done).toResolve();
     });
 
@@ -312,6 +398,8 @@ describe('loadObj', function() {
 
     it('does not load resources outside of the obj directory when secure is true', function(done) {
         var options = clone(defaultOptions);
+        var spy = jasmine.createSpy('logger');
+        options.logger = spy;
         options.secure = true;
 
         expect(loadObj(objExternalResourcesUrl, options)
@@ -320,8 +408,30 @@ describe('loadObj', function() {
                 expect(data.images[imagePath]).toBeUndefined();
                 expect(data.materials.MaterialTextured).toBeDefined();
                 expect(data.materials.Material).toBeUndefined(); // Not in directory, so not included
-                expect(console.log.calls.argsFor(0)[0].indexOf('Could not read mtl file') >= 0).toBe(true);
-                expect(console.log.calls.argsFor(1)[0].indexOf('Could not read image file') >= 0).toBe(true);
+                expect(spy.calls.argsFor(0)[0].indexOf('The material file is outside of the obj directory and the secure flag is true. Attempting to read the material file from within the obj directory instead.') >= 0).toBe(true);
+                expect(spy.calls.argsFor(1)[0].indexOf('ENOENT') >= 0).toBe(true);
+                expect(spy.calls.argsFor(2)[0].indexOf('Could not read material file') >= 0).toBe(true);
+            }), done).toResolve();
+    });
+
+    it('loads resources from root directory when the .mtl path does not exist', function(done) {
+        expect(loadObj(objResourcesInRootUrl, defaultOptions)
+            .then(function(data) {
+                var material = data.materials['Material'];
+                var image = data.images[material.diffuseTexture];
+                expect(image.source).toBeDefined();
+            }), done).toResolve();
+    });
+
+    it('loads resources from root directory when the .mtl path is outside of the obj directory and secure is true', function(done) {
+        var options = clone(defaultOptions);
+        options.secure = true;
+        expect(loadObj(objExternalResourcesInRootUrl, options)
+            .then(function(data) {
+                expect(Object.keys(data.materials).length).toBe(2);
+                var material = data.materials['MaterialTextured'];
+                var image = data.images[material.diffuseTexture];
+                expect(image.source).toBeDefined();
             }), done).toResolve();
     });
 
@@ -335,12 +445,19 @@ describe('loadObj', function() {
     });
 
     it('loads obj with missing texture', function(done) {
-        expect(loadObj(objMissingTextureUrl, defaultOptions)
+        var options = clone(defaultOptions);
+        var spy = jasmine.createSpy('logger');
+        options.logger = spy;
+
+        expect(loadObj(objMissingTextureUrl, options)
             .then(function(data) {
                 var imagePath = getImagePath(objMissingTextureUrl, 'cesium.png');
                 expect(data.images[imagePath]).toBeUndefined();
                 expect(data.materials.Material.diffuseTexture).toEqual(imagePath);
-                expect(console.log.calls.argsFor(0)[0].indexOf('Could not read image file') >= 0).toBe(true);
+                expect(spy.calls.argsFor(0)[0].indexOf('ENOENT') >= 0).toBe(true);
+                expect(spy.calls.argsFor(1)[0].indexOf('Attempting to read the image file from within the obj directory instead.') >= 0).toBe(true);
+                expect(spy.calls.argsFor(2)[0].indexOf('ENOENT') >= 0).toBe(true);
+                expect(spy.calls.argsFor(3)[0].indexOf('Could not read image file') >= 0).toBe(true);
             }), done).toResolve();
     });
 
@@ -417,11 +534,15 @@ describe('loadObj', function() {
             }), done).toResolve();
     });
 
-    it('discards faces that don\'t use the same attributes as other faces in the primitive', function(done) {
+    it('separates faces that don\'t use the same attributes as other faces in the primitive', function(done) {
         expect(loadObj(objMixedAttributesUrl, defaultOptions)
             .then(function(data) {
-                var primitive = getPrimitives(data)[0];
-                expect(primitive.indices.length).toBe(18); // 3 faces removed
+                var primitives = getPrimitives(data);
+                expect(primitives.length).toBe(4);
+                expect(primitives[0].indices.length).toBe(18); // 6 faces
+                expect(primitives[1].indices.length).toBe(6); // 2 faces
+                expect(primitives[2].indices.length).toBe(6); // 2 faces
+                expect(primitives[3].indices.length).toBe(6); // 2 faces
             }), done).toResolve();
     });