Matchmove Extended

Hi, I’m working on a shot that has a camera move I would like to extend. At the beginning of the shot the camera tilts down, but doesn’t start tilted up high enough to see the top of a tall building. I want to extend the tilt so we see the top of the building at the start of the shot and as the camera tilts down blend it into the existing tilt motion that already exists in the live action shot. Seems pretty straight forward, right?! : ))
The shot was motion tracked in SynthEyes and brought into Fusion .The tall building was collaged from multiple stills using the same camera and lens. The main reason I did the Syntheyes work was to get rid of the lens distortion, which would allow me to undistort the stills images for a better result in blending them together and combining that image back into the Live Action part of the shot, as that would be undistorted too.
I have a 3D scene set up in Fusion with the collaged photo of the building mapped to an image plane which has been roto’ed and positioned so that it blends into the Live Action shot (see attached screen shots).
The part of the Live Action shot (where the camera starts moving at a constant speed, is about frame 270, so this is the point where the two tilting movements can be “connected” I want the camera to transition from the tilt down, on the stills ImagePlane, to the Live Action portion of the shot.
As I do not have much experience with Fusion, or this technique, my first impulse was to delete the X rotation key frames, for the tilt I don’t need, before frame 270, create a new key frame of the camera looking up at the desired angle, and simply match the speed of the tilt with the spline editor. This works great as the camera tilts down over the ImagePlane (still photograph of the building, screen grab 01) but as soon as the edge of the roto appears, and we see the Live Action element underneath, it is not lining up any more, as the Live Action is essentially moving with the camera (screen grab 02). To fix this I thought I could simply animate an offset for the Live Action, so it counteracts the motion of the camera until frame 270. Once the live action element reaches the alignment point with the ImagePlane, where the steady speed part of the matchmove kicks in, everything is good again (screen grab 03). Unfortunately I have not been able to find a way to off sett the Live Action. At this point I thought, rather than banging my head against a brick wall, I would ask the experts… YOU! : ) and see if this can be solved easily or maybe there is a smarter, more elegant, way that I am completely unaware of. Any constructive feedback would be appreciated.
Cheers - F

I am not sure if I understand you correctly, but you want to make it longer at the beginning right?
I wouldn't go and delete any keyframes. What you could try is move the start time of the footage and the keyframes from Syntheyes with the extra length of the shot. Say you want to add 75 frames, then move everything to frame 75.
Then go and find the first keyframe of the camera move and in the spline editor *extrapolate* the curves from the camera. I think there's even a function for that in the right-click section (I'm not at my system now so I can't check) this way you may get a pretty smooth move that looks like the original. Maybe add a little bit of noisy movement in there for that first section to make it feel more natural.
I hope this gives you an idea on how you might be able to approach this.

HI, it's a complicated move and unfortunately the approach I was taking didn't work. I will continue to search for am answer.

If I understand correctly your problem is not in creating the camera move you want but sliding projection due to new move? Solution to this is simple, use original matchmoved camera for projection (and hold first frame in the beginning for the part where new move is extended beyond original length) but use your new camera with modified/extended move for rendering the projection. The logic is basically the same as for example in the case where you want to project a single still onto geometry and do a camera move. You project from one camera and move another.