diff --git a/lib/loadMtl.js b/lib/loadMtl.js
index a9953bf..3eba5aa 100644
--- a/lib/loadMtl.js
+++ b/lib/loadMtl.js
@@ -846,19 +846,14 @@ function createSpecularGlossinessMaterial(material, options) {
   } else {
     const alpha = material.alpha;
     diffuseFactor[3] = alpha;
-
-    if (options.doubleSidedMaterial) {
-      transparent = true;
-    } else {
-      transparent = alpha < 1.0;
-    }
+    transparent = alpha < 1.0;
   }
 
   if (defined(diffuseTexture)) {
     transparent = transparent || diffuseTexture.transparent;
   }
 
-  const doubleSided = transparent;
+  const doubleSided = transparent || options.doubleSidedMaterial;
   const alphaMode = transparent ? "BLEND" : "OPAQUE";
 
   return {
@@ -932,19 +927,14 @@ function createMetallicRoughnessMaterial(material, options) {
   } else {
     const alpha = material.alpha;
     baseColorFactor[3] = alpha;
-
-    if (options.doubleSidedMaterial) {
-      transparent = true;
-    } else {
-      transparent = alpha < 1.0;
-    }
+    transparent = alpha < 1.0;
   }
 
   if (defined(baseColorTexture)) {
     transparent = transparent || baseColorTexture.transparent;
   }
 
-  const doubleSided = transparent;
+  const doubleSided = transparent || options.doubleSidedMaterial;
   const alphaMode = transparent ? "BLEND" : "OPAQUE";
 
   return {