I'm working on a project which involves 3d space (using camera tracker). Everything is going fine until I needed to turn on motion blur for a layer. When i switched it on for the composition, things start to get weird. If you play the video, the null objects visibly "rotate" instantly, move from spot to spot randomly, and it's obvious that something is not right. When i turn off the motion blur, the object right themselves.
Does anyone have any suggestions? I think i can work through it by creating a new composition then dropping the existing into that and turning on motion blur there, but i would rather be able to work with it in the same comp.
I'm working with 1920x1080p footage 30 fps in CS5.5 on a macbook pro 2.52ghz intel core 2 duo. If you need any other info just let me know.
The only thing that I can think of that may cause the problem is OPEN GL acceleration. Try turning it off.
If that's not it, then I need a lot more info about the project, like a screenshot. There's nothing about motion blur that would change orientation or position of layers. There are a bunch of other things that may cause this, but without looking at your comp I would only be guessing.
Here is a screenshot of my composition. If you need more details just let me know.
I turned off openGL in the video preview preferences menu, but that didn't make a difference. That null object in the frame continues to "stutter" around. At one point, the lens flare just randomly popped up (as the wrong color). It seems to just randomly mess things up. I'm using optical flares and camera tracker. When i created a new comp with camera tracker and motion blur things started going weird again, which makes me think that there is some weird issue between the two? I'm figuring out a different way to do the effect w/ the motion blur, but this is still frustrating.
Show us a shot with the motion blur turned off at the same point in time so we can see what is fouled up. It's hard to see here. I can only see one layer boundary and what I assume is a null. . I can't see all the layers. I don't see a null in the timeline. I'm assuming you only have 1 camera.
The first image has motion blur turned off. The second motion blur is turned on, same spot on the timeline. Most of my layers are sparks and stuff that dissapate very quickly, but the video/layer keeps going to let the debris clear out. I have 1 camera. The null objects are named something like "CameraObjectx".
Got it, took me a while to figure out how to share files via dropbox..
OK, here's my best guess. When you turn on motion blur time samples differently. The keyframes that are causing the problems are at a z rotation for the camera of 179º. This made me think you were experiencing a gimbal lock with your camera moves. When the camera gimbal locks the camera orientation flips. It has nothing to do with motion blur being enabled on the layers.
I seldom apply tracking data directly to a camera for this reason. I almost always apply the tracking data to a null then parent the camera to the null. This will prevent gimbal lock problems with the camera.
There is a solution that may work for you. Open up the composition settings, the Advanced tab and change the Shutter phase to 0º. This should prevent the gimbal lock that you're getting. I wouldn't call this a bug, but a better workflow would have prevented the problem in the first place.
Thanks for the suggestion. I tried it and it seemed like the weirdness has gone away. But now a new set of problems has come up. When i get to the point in the rendering where the lense flare comes in, i get an After Effects Crash while invoking optical flare plugin. It then follows up with a crash error while invoking "advanced 3d" rendering.
I had completed my desired shot and rendered it out (before i changed the shutter phase). It looked pretty good except for a couple weird moments where its like a layer changed position then quick changed back. I can't tell if setting the shutter phase to 0 will fix that because now i can't even complete a render! Any ideas?
I can't imagine that changing shutter phase would cause a crash. Make sure the Optical Flair plug-in is updated to the latest version. It's known to have some serious problems before the update. Also, make sure that AE is up to date.
If that doesn't do it make sure that you're purging frames. The setting is in the Secret preferences. You access them by holding down the shift key while clicking on Preferences>General. Then click on the bottom option Secret, and purge every 3 or 4 frames.
The last suggestion, without moving all of the keyframes for the camera to a null and using the parenting trick would be to delete the keyframes that are causing the problem and returning the Shutter Phase to -180º.
Thank you for your suggestions. When setting the purge frames, should the box above be checked?
I tried rendering out again, and received the same crash (optical flares, then advanced 3d). Everything seems to be up to date.
I'm not sure I understood the last suggestion though, wouldn't deleting the camera's keyframes make it loose its path in 3d space? All of my elements are relying on the camera tracking, so i don't know how that would effect them.
This doesn't result in a crash, but i had to close After Effects because now i can't do anything without getting this error. It seems like 1 problem is leading to another. Is there a way to "cleanse" after effects?
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