I am using Autocad, I export to 3D Dwf (.dwf format) and upload to the sketchfab website. When I go to assign materials, it shows Scene-Root only, no material drop-down list. I have at least a hundred models I’ve uploaded and have never had this issue. I know AutoCAD doesn’t have material mapping, so I don’t have any .mtl files to upload. Usually, I just upload my dwf, then select my material 1, 2, 3, etc. on sketchfab and make my items the colors I want. I have tried re-exporting, re-uploading and resaving the file several times but to no avail. Can anyone help me?