Merge branch 'martinbudden-render_if'

readme.md

@@ -6098,6 +6098,7 @@ Global constants, functions and modules. This file is used directly or indirectl
 | ```ellipse(xr, yr)``` | Draw an ellipse |
 | ```extrude_if(h, center = true)``` | Extrudes 2D object to 3D when ```h``` is nonzero, otherwise leaves it 2D |
 | ```hflip(flip=true)``` | Invert children by doing a 180° flip around the Y axis |
+| ```render_if(render = true, convexity = 2)``` | Renders an object if ```render``` is true, otherwise leaves it unrendered |
 | ```right_triangle(width, height, h, center = true)``` | A right angled triangle with the 90° corner at the origin. 3D when ```h``` is nonzero, otherwise 2D |
 | ```semi_circle(r, d = undef)``` | A semi circle in the positive Y domain |
 | ```translate_z(z)``` | Shortcut for Z only translations |

utils/core/global.scad

@@ -52,6 +52,13 @@ function slice(list, start = 0, end = undef) = let( //! Slice a list or string w
     ) is_string(list) ? slice_str(list, start, end) : [for(i = [start : 1 : end - 1]) list[i]];
 
 
+module render_if(render = true, convexity = 2)      //! Renders an object if ```render``` is true, otherwise leaves it unrendered
+    if (render)
+        render(convexity = convexity)
+            children();
+    else
+        children();
+
 module extrude_if(h, center = true)                 //! Extrudes 2D object to 3D when ```h``` is nonzero, otherwise leaves it 2D
     if(h)
         linear_extrude(h, center = center, convexity = 2) // 3D