This is one of those dumb questions, at least to some of you, but while I've been around computers for a lot of years, I'm new to 3D graphics. Can anyone explain in simple language to me what the relationship is between cr2, obj and tex files is? I understand that the 'tex' files give a figure it's outward appearance and I think that the 'cr2' files give it its 3D configuration. But then, what does the 'obj' file do?