Sorry, I'm referring to the materials as layers. I am guessing it is a problem in AutoCAD. I'm taking a Solidworks file, saving it as a step file. Then I import it into AutoCAD and explode it. I then create a layer for every different material. I created 12 different layers in AutoCAD so there would be 12 different materials in Chief Architect. I am then able to apply different wood grain, metal finishes and fabrics to the symbol. But with this model I am missing the materials I have named Layers 4, 5, 6, 7, and 12.