www.ssontech.com

[Malkyne]

So, I have a very unusual scene that is making me pull my hair out, and it's not my footage, so I don't have the liberty of reshooting it. Essentially, there are two men standing in a room, facing each other, lit more-or-less from above. The camera begins behind the back of one of the two men, pans along a track on a counter-clockwise arc to the right, while tilting the camera upwards, so that ultimately, both men are seen in profile, and something (which is to be added in later, using CG) has been revealed on the ceiling. To add to my problems, the background is also exceedingly dark, and there's a lot of noise back there, so there's not a lot I can track in the background. Moreover, the men, while nearly still, are exhibiting a small amount of motion, but I can't mask them out, because at the beginning of the shot, there's almost nothing else to track.

Now, miraculously, SynthEyes is managing to produce a pretty good camera track from this shot, in spite of the various problems. It really only seems to need some clean-up work in the places where there's a lot of motion in the foreground subjects. However, what's absolutely killing me is that I can't set up a coordinate system for the shot. I would like to use the ceiling as the "ground plane," since that is where I'm going to put the CG object that is being added to the scene, but there is nothing distinct on the ceiling that is visible throughout the entire shot. There is a lighting framework up there that I can use later in the shot, but SynthEyes refuses to solve, if I set the coordinate system up based on features that are not visible at the beginning of the shot.

So, my question is: Does anyone have any good recommendations for how to best establish a coordinate system for a shot like this? (I am not at liberty to share the footage, I'm afraid.)

[Pretty Vacant]

If you have usable points on the ceiling, you can use them to set up your coordinate system even if you have to set your Start & End frames when the trackers aren't enabled (you have tried manually changing these to frames on which your constrained points are enabled, right?)

If you absolutely have to have Start & End frames in which the points aren't enabled, solve without constraining, and then Refine with the constraints.

Works like a charm.

Almost always

[Malkyne]

[LFGabel]

Brute force always works. If you have a pretty stable solve, then estimating the ceiling by hand in your 3d app may work for you. I've done that a lot to make shots work.