But, I only want four of the six sides to expand.

For example, I have a rather flat 3D rectangle something like a book. The four sides representing the edges of the book, ie not the front or the back, are selected. In one operation of the mouse I want to expand and contract those four sides in unison about the central axis. Is this possible?

Say, thanks everyone. That was helpful.

I don't know if SketchUp is what I am looking for. Here is what I want to do. I want to make a video which, unlike the "walk-throughs" I have seen posted, would show, for example, a square actually being pulled into a cube. That is, not only do I want to pull a square into a cube but I want to record that specific action on video. Does SketchUp have this capability? Thanks in advance.