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Motion Tracking – Corner Pin NIghtmares
Hi —
I’m doing some motion tracking using perspective corner pin on some HD footage, and I am getting very inconsistent and maddening results.
Never mind the track itself, it’s fine. It’s the placement of the target layer that is driving me crazy. The attach points are offscreen or off center. Sometimes I can fix this by attaching the corner pin data to a null and moving the null, but sometimes I can’t. I have tried pick whipping the corner pin effect corners to the attach point data directly, but that doesn’t always work either …. it feels like either corrupt tracking data, or a bug in AE7, possibly around tracking HD footage. I haven’t had this problem with previous AE versions and I’ve actually seen this issue all over the forums without many answers.
I guess at this point I have a couple of questions around the attach point and feature center data … should attach point be a literal position on my comp? It’s actually based on anchor point, isn’t it. Any idea how to calculate the offset. And, everything I read says I don’t need feature center data at all, but when I eliminate those keyframes, it seems to corrupt my tracker …
Help, I’m losing my sh*t.
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6 Replies
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What are trying to do exactly? What is the shot? maybe there is a simpler work around
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It’s a shot of guy working at a computer monitor. It was shot on greenscreen, with markers on the screen. It was shot with the camer on a big old crane and a the guy on a turntable which revolves at the same time, so the shot starts above and the guy turns as the crane lowers and zooms in to his screen.
I’m not having a problem getting good tracking accuracy, but for some reason the tracking points – attach point and feature center data, are showing up offscreen. I understand there is a relationship between my anchor point and my tracking data, so I have tried parenting the target to a null and applyinmg the track to the null, but I’m still having some weird issues.
I’ve done this a fair amount in the past, and haven’t had this problem. I’m wondering if it’s because I’m working with HD/AE 7, or if it’s me.
Thanks for any help, I really appreciate it
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So basically the guy is turning as the camera comes down? I could understand why it would be difficult to track and replace the screen. Not only is the screen turning (which is really hard to track), but there must be some motion blur in there unless the guy isn’t turning very fast.
If the guy really is just turning on himself, why not try animating most of the thing by hand?
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I think you’re maybe missing the point … I’ve tracked the thing fine. My track is accurate. I know all about motion blur. That isn’t the problem either, I know how to make tracked footage look good. The problem is that the target object doens’t get put in remotely the right place, and I’m unable to fix it through other methods. Furthermore, I have a workaround, which is to track it in Silhouette, the roto tool from SilhouetteFX, and export the tracker data from there and apply it to my layer back in AE. That works, but it’s a pain in the ass and it would be great if AE’s tracker worked right.
My main questions are: is this a bug? Is there a way, through changing the relationship between feature center, anchor point and attach point to fix the problem, possibly using a null object? And has anyone else has this issue.
Thanks – also, I’ve typed a lot around this, so please read the whole thread carefully before answering.
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Just for the record … I went back to AE 6.5 and it worked beautifully, so I logged a bug w/Adobe.
I’d love to hear if anyone else is having this issue.
D
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Just an update … I don’t know if you’d call this a bug or not, but I solved this problem. It only happens when you’re tracking and your source footage is less than full res. My viewer resolution was set at half when I was having this issue. When I set it to full, the tracker worked fine.
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