Perspective as it is and can be used in Apo 3D is the subject of the latest article/post on my blog.
[link] under the category of Parallel Perspective.
It's in the form of a tutorial as there are illustrations showing how it works and how it can be used, especially in relationship to getting stereo images. But anyone using the 3D hack versions will want to understand the Perspective control.
You're invited to stop in and check things out. Feel free to provide comments or questions as those are helpful as more new content is being written and designed.
Thanks!