How Do I Get Rid of This Glitch?

I have a flat mesh overlaying a hole in the side of this cube. They’re only connected as parent/child and the mesh sits on the side of the cube. The mesh uses shape keys, if that matters. As you can see, there’s a glitch in the rendered image. What do I have to do to get rid of it?


Attachments


Don’t have faces overlapping.

I agree with Richard. The glitch you’re seeing is common when you have two objects with faces in exactly the same place. The rendering algorithm doesn’t know which you intended, so it poorly uses both.

Okay, that’s obviously the problem. So how do I take a mesh plane that I built and attach it to the side of a cube? I tried cutting a hole in the cube to fit the mesh plane in with a slight overlap so the seam won’t show, but I can’t figure out how to connect the plane as part of the cube so that it’s one mesh object. If I go into edit mode, I can only edit one object at a time, so I can’t connect the vertices of the plane to the vertices of the cube. How do I get around this?

The mesh plane has a bunch of shape keys attached to it, so I don’t want to have to rebuild it and redo all the shape keys.