This should be easy right? (Mocha/AE Question)

sdeming

sdeming

Member
I've spent about three hours on this shot and I cannot figure out why this is so difficult! Here, I made a video to show you my question rather than attempt to explain it..


Now, I've tried aligning the track to the surface, I've tried adjusting the track, but for some reason the buildings seem to grow. This is not parallax. I've removed the scaling in the null object, and I've triple confirmed that the buildings have no animation in or on the comp.

I've watched Andrews 'set extension' tutorial a billion times before this doing similar work and I've never had this issue. As you can see here, I did the panning up shot, and it worked just fine. Easy! And the kicker is that I've done ton of stuff like this before. It's this one shot that's giving me a hard time....

So, I ask for your help. Thanks in advance.
 
It's not easy to tell but one thing using those far off buildings as the source for mocha splines to track the camera move is going to have issues. The further from the camera, the less perspective data is going to be available to accurately match the camera pan. Try using mocha on that pile of rubble and dirt on the road and maybe the side of the building. When tracking a camera move I always try to use the ground close to the camera, it usually works better. (though not always, every shot has it's own headaches)

Be sure and enable perspective (and maybe turn off shear and scale). Might need to try it several ways. When you apply the track into AE turn off the anchor point and scale keyframes on the null. You should be able to get a solid track with that shot. If it's still not working, in AE look at the null's curves and if necessary select the bad points and smooth them(use the smoother) or just set them to the correct values. You may very well have to tweak every frame on the null to fix little issues.

One thing that might help you is to bring in a crosshair-target image(make one quick in Photoshop) and place it on a point that should stay rock steady (like the top of a telephone pole) and parent it to the null and then see how it tracks. Might give you some idea of how the tracking isn't working (vs trying to figure it out by looking at the larger building image).
 
iunknown said:
sdeming,
maybe download the full version 30 day trial. The one that ships with AE is limited.
Click to expand...

There's no difference in the tracking between the two, only differences aren't really applicable to people solely using AE.

To the OP, it'd be easier for people to help you if you can just upload the shot so we can watch it without the camera shake and extra compression on it. It's hard to give advice on a tracking shot if you're seeing two sets of camera moves, one in the shot and one in the shot of the shot, you know?

Beyond that, select your layer with your tracking keys on it and press U to reveal all the keyframes and go through the trouble section frame by frame and watch the numerical values to see what's happening. Also press UU to reveal all modified properties and see if anything else has been changed.

Really, with a shot like that with the background stuff so far in the distance you can probably get away with one point (position tracking) in AE. From what I can tell there's very little movement in the shot and the movement that far out is so minimal you don't need scale info.
 
sdeming said:
I've spent about three hours on this shot and I cannot figure out why this is so difficult! Here, I made a video to show you my question rather than attempt to explain it..
...

Now, I've tried aligning the track to the surface, I've tried adjusting the track, but for some reason the buildings seem to grow. This is not parallax. I've removed the scaling in the null object, and I've triple confirmed that the buildings have no animation in or on the comp.

I've watched Andrews 'set extension' tutorial a billion times before this doing similar work and I've never had this issue. As you can see here, I did the panning up shot, and it worked just fine. Easy! And the kicker is that I've done ton of stuff like this before. It's this one shot that's giving me a hard time....

So, I ask for your help. Thanks in advance.
Click to expand...

I believe the process you are doing is called 'matched move', where the 3-d model/virtual camera is given a 'track' which matches the real world camera. This allows the virtual world objects to appear as if they were in the 'real(tm)' world, relative to the camera motion.

There's a free tool for Windows and Linux

http://www.digilab.uni-hannover.de/docs/manual.html

And here is a pointer to a blurb on a tutorial for getting the derived camera movement into After Effects...
http://aeportal.blogspot.com/2010/08/voodoo-camera-tracker-free-matchmove.html

And here's the tutorial...

http://ae.tutsplus.com/tutorials/workflow/free-3d-matchmoving-alternative-for-after-effects/

I've not attempted this, as I don't have a Windows box, and I've not setup my linux boxes for general 'video/graphics' processing... I should do that one of these days...

But it does go through the steps of match moving...
 
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