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Inverse Track+Puppet Pin Expression to Freeze Points
I’ve had great success with tracking layers onto flexible moving objects in a scene by attaching puppet pins to point tracking data in the past. For example, making a fake tattoo stick to a fat guy’s jiggling skin as he runs.
Now I’m trying to do pretty much the exact opposite, and I’m stuck on the vector math.
I have a shot of an umbrella that is blowing in the wind and rain. I need to freeze the blowing motion as much as possible, so my idea is to track various points like the corners of the umbrella, and map them to puppet pins that will nail it down to the screen by compensating for the motion. It works ok if I roto it by hand, but it would be a lot faster and more accurate if I could use trackers.
Ideas? Thanks in advance!
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2 Replies
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So, using the reverse stabilize pre-comp trick as a point of departure, I’m currently using this solution, and it seems to be working:
-Track a point
-Make a solid the same size as the comp, and pickwhip the anchor point to the tracker attach point
-Make a null, and position it over the track point at the first frame
-parent the null to the solid
-make a puppet pin on the target layer
-Add Dan’s code found elsewhere to get world position from the null:There has to be an easier way, but this does seem to work….
L = thisComp.layer("child null");
L.toWorld(L.anchorPoint); -
Alternate approach:
Find the part in the footage where the umbrella is moving the least in the wind and make a seamless loop out of it, long enough to not be noticeable. Overlay on fluttering umbrella, perhaps slightly enlarging the looped copy if the umbrella moves around.
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