Hi Angelina, Yes,that is exactly the problem in 3ds - it cannot "recognise" back faces so the only way of handling this is to keep your model consistently "clean" of them. The reason is that SU is a surface modeler and "pretends" or "fakes" solids by making hollow objects always with their normals out. This is also the problem with to sided materials.

Hi again, I had problems ın SU Materials so I converted the file to 3ds and imported the whole model in 3D max.. As SU works wıth the hollow objects in 3dmax the faces somehow ımported inside out.That is why the faces appeared to be black when rendered.. The solution of the problem; 1-Converting the faces by modifying all the objects to normal one by one (Takes hell of a time )) 2-Checking the two sided materials In material editor (Which it did not work when I tried it) 3-I would be please to be informed if you know an other way to fix the problem ... PS: This is the comment/answer based on the prior questions above.. Regards ng