I have an image plane of an elevator shaft shot from the bottom pointed up and at an angle. I'm having a heck of a time trying to get a 3D elevator model to slide down the shaft and keep the right perspective. Can anyone shed some light on the correct procedure of how to match perspectives?
I would start by placing a tall poly cube in the position of the shaft itself. If you don't have details about camera position and orientation, and the scale of the scene recorded, then it's just a question of eyeballing it.
Once you have a shaft in position, it should be easy enough to use it as a guide for the elevator object.
Also, note that if the camera used a lens that introduces spherical distortion (straight lines become curved as they move towards the edges of the frame) you won't be able to match it well with your CG scene--CG perspective works in a different way.
If you want more detailed advice, post a link to your image plane.
Try out Steve's advice: it's worked for me in the past. Try to block in some shapes, like the shaft as a polycube, perhaps some horizontal shapes as well (piping, door, whatever) and try to make everything fit by tweaking, tweaking, tweaking.
Make sure you have the camera settings as close to the live action camera as well, though this is something I'm not an expert in and as Steve said rightly, CG cameras just can't match some distortions introduced by real word lenses.