I'm facing a project that will require split screens and picture-in-picture effects. The easiest way I can figure this out is to use transitions, and prevent the transition from progressing from 0% to 100%. Is there any way to do that in Vegas, or must I figure it out in the Crop & Pan window?
Keep your media PiP and split screen media on separate tracks. Then use Track Motion at the track level to key frame the effects. You can use a 3rd track as a background for the split screen, for example the way CNN does.
If you cannot figure out how to control the transitions, render the PiP and Spit screen footage to an intermediate. Then transition as you normally would.
Agree with astar. One you get a handle on using tracks, track motion, and pan/crop, you'll find it faster, easier, and much more capable than using transitions. This sort of thing really isn't what transitions were made for.