Assigning materials to groups and components
Everybody knows that faces in SketchUp can be painted with different materials. What lots of designers don’t know is that you can apply materials to groups and components, too. The following illustration shows the Entity Info dialog box, which is a great place to see which materials are applied to your geometry.
When you paint a group or component red, only the faces inside it that are painted with the Default* material turn red. Faces that have already been painted with another material don’t change at all.
This trick also works with groups and components that are nested inside one another. When you apply a material to a top level group or component, all the Default-colored faces that are inside nested, Default-colored groups and components inherit that material automatically. The following diagram is my best attempt at a visual explanation of this phenomenon.
*SketchUp automatically applies the Default material to faces you create from scratch. You can also paint anything with the Default material at any time; just pick it in the Materials Browser (which looks completely different on PCs and Macs.)
As you can see, this technique is a godsend for building complicated objects that need to change color easily. In the case of the George Nelson Marshmallow Sofa in the images that follow, the cushions are individual component instances nested inside the main Sofa component. These are assigned the Default material.
All of the metal and rubber frame pieces are also groups and components, but their faces are all assigned specific materials.
When you use the Paint Bucket to paint a color—in this case, orange—on the main Marshmallow Sofa component, only the cushions take on that color. Everything not assigned to the Default material stays exactly the way it is.