the base become friable - what's the matter

[Rstan]

I had the object - plain surface as bottom - ground. But I don't know what's the matter, when I edit object localize on it. I made link; unlink operations for this object. But my plain surface ocassionally became friable, and my avi fall into it

[Rolig Loon]

If your object is phantom, select it with your edit tool.  Choose the Object tab and UNcheck the Phantom box.