Hi, I think the script "layers_materials.rb" will help you. What it does: "Manages layers and materials as the "color by layer" display mode does. 4 options to create layers or materials corresponding with materials and layers, to repaint faces based on their layer or to change their layer based on their materials." Download it here: http://www.crai.archi.fr/RubyLibraryDepot/Ruby/em_ren_page.htm Hope this helps