Hi all,

I need to work out a method for matching perspective in 3d scenes (Poser) to the perspective in 2d images.  Didn't find any easy buttons for this, so I'm making up my own.

Seems like what I need to do is establish vanishing lines, trace them back to the horizon line, and then try my best to eyeball my 3d perspective into place with the perspective guides in Poser.

So, right now I'm working on how to get those vanishing lines extended all the way to the horizon.  Obviously I increase the canvas size.

Then, the best I can come up with is using the line tool to follow whatever straight architectural-type lines I have.  Trouble is, to be accurate I have to zoom in as far as possible, which means I can't make the line very long.  When I zoom out, I can barely see the line, so I can't accurately use the line tool again using the original as a guide.  Is there a way I can automatically turn a line segment into a ray, for lack of a better term?  That is, take the line segment I've made and extend it out to infinity?  If I need to use a different tool, maybe a vector tool, that's fine too, the task remains the same.