& what one's need is.  I have a tip to share. Today when rendering a scene I noticed one of my M4's rendered all white aka texturless. Upon investigating the matter I noticed that when picking any texture on it, the surface line was jumping to another M4 in my scene as I called Reality. I then realized I had 2 M4's that loaded as M4 (2) all I has to do was rename one of the twos to (3) and all textures loaded normally.