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3D Camera Tracking exports unreliable rotation coordinates to C4D

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Andrew Matthews
3D Camera Tracking exports unreliable rotation coordinates to C4D
on Jan 18, 2014 at 8:25:59 pm

Hi, I've just started using AE CC's 3D Camera Tracker, which at first seemed awesome, but I've run into a problem I don't know how to fix.

Basically, I discovered the problem when I imported an AE Comp into Cinema 4D and though at first everything seemed fine, when I applied a motion blur with the physical renderer, I discovered an occasional, twist-like smear on the motion blur.

A bit more investigation revealed that the camera rotation coordinates exported by AE would occasionally jump a full 360 degrees. In other words, go from 0 to 360 in one frame. This jump is normally imperceptible, as 0 and 360 is essentially the same position, but a motion blur takes this one-frame spin into account and unfortunately (but correctly) adds a circular motion smear to the frame.

I've been searching all day for someone with the same problem without success. Has anyone ever encountered AE's 3D Camera Tracking exporting rotation coordinates that leap like this? If so, is there a fix?

I'm using a Mac with AE CC and C4D R14.042. I'm using the MAXON CINEMA 4D EXPORTER plugin in After Effects to export the comp.

Much thanks,
Andrew


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momcilo bozic
Re: 3D Camera Tracking exports unreliable rotation coordinates to C4D
on Jan 19, 2014 at 12:33:07 am

I'd Say
Maybe check your AE Comp
maybe you did those keyframes in After Effects but the AE does not have that ability of motion Blur like C4D has

worth trying


M

digital cinematography, montage, directing


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Darby Edelen
Re: 3D Camera Tracking exports unreliable rotation coordinates to C4D
on Jan 19, 2014 at 6:17:09 am

[Andrew Matthews] "I'm using a Mac with AE CC and C4D R14.042. I'm using the MAXON CINEMA 4D EXPORTER plugin in After Effects to export the comp."

I've just run a test with the Cinema 4D Exporter going from CS6 to R15 and it looks like C4D miraculously fixes the jump across the 0-360° boundary (at least with those versions).

I've given a few ideas a try but can't come up with a really good way to eliminate this behavior. There is one option that may work but it requires rotating the entire scene around the origin of the camera move.

To do that you'd go to the first frame of the track, create a 3D Null and shift-parent it to the tracked camera (moving it exactly to the camera's position/orientation). Then unparent the Null and parent the tracked camera (as well as any 3D layers you need to move with the scene) to the Null. The camera's transforms should all be zero'd out now. Enter a new orientation in the Null's Orientation property to re-orient the entire camera move (while keeping all transforms relative).

For example, if your camera was oriented (and now your Null is oriented) at 359°, 2°, 5° then you'd want to rotate the Null on any axes that dropped below 0° (and wrapped around) on the camera.

You can easily see where these values have wrapped around by selecting the Orientation property of the camera and looking at the Value Graph Editor in the timeline. You should also be able to get a sense for how far across the 360° line they go. If a value drops from 360° all the way to 350° then you'd want to enter at least 10° in that axes on the Null.

If the camera rotates quite a bit this may be difficult.

When you're done you can unparent the camera from the Null and check the new orientation values in the graph editor. If they're good then you're set, if not then undo the unparenting and modify the orientation further.

Darby Edelen


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Andrew Matthews
Re: 3D Camera Tracking exports unreliable rotation coordinates to C4D
on Jan 19, 2014 at 4:19:07 pm

Thanks,

I was afraid something like this would be my only option. It's only a 10 second shot with two jumps across the boundary, so it shouldn't be too tough, but I was really hoping that this integration between the programs would make future projects like this a breeze.

Thanks though!

-Andrew


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Andrew Matthews
Re: 3D Camera Tracking exports unreliable rotation coordinates to C4D
on Jan 19, 2014 at 5:24:02 pm
Last Edited By Andrew Matthews on Jan 19, 2014 at 5:30:44 pm

I can't quite seem to get this to work. Even if I use a null to change the orientation of the whole scene, the camera retains its HPB coordinates, which always jump the 0, 360° boundary. Parenting the camera to a null does not zero out it's orientation values. (For some reason, it's only H and B that jump from 1° to 359°, say. P goes into negatives, as I wish the others would.)

In the timeline, I can easily select all the keyframes that need to be adjusted by -360°. Is it possible to adjust multiple keyframes by a certain value at once? I know I can do it by dragging them, but that's not nearly exact enough. I can also just type a number into the Key Value under Key Properties, but that moves all keyframes to that value. I want to adjust them all by a certain amount. Like, I wish I could type into Key Value something that subtracts a value of 360 from all keyframes, keeping them relative to each other. Seems like this should be possible.


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Darby Edelen
Re: 3D Camera Tracking exports unreliable rotation coordinates to C4D
on Jan 19, 2014 at 7:29:42 pm

I realized after I posted last night that I was providing an After Effects "solution" to something that might require work on both ends of the pipeline. I think it'd be hard to see exactly what you're getting without a project file, could you upload an AE CS6 project file with just the camera animation (and maybe some locator Nulls) here so I can take a look?

One interesting thing I noticed was that the camera I exported from AE to C4D came in with a ZYX rotation order (to match AE I assume) rather than C4D's default HPB.

Darby Edelen


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Thomas Downing
Re: 3D Camera Tracking exports unreliable rotation coordinates to C4D
on Mar 4, 2014 at 5:33:23 pm

I ran into a similar problem. Here's how to modify multiple keyframe values at the same time.

  • Go to the "Animation" layout view.
  • Hit "Space" to go to "F-Curve" view.
  • Click and drag a box around the keyframes that are off by 360degrees.
  • In the Attribute manager, you should see Key Value...... <>
  • Click on the <>.
  • Type x-360 (or x+360) and this will modify all the values by the amount you need (in this case 360)


That should do the trick and allow you to use the Physical Renderer's motion blur with a 3D Camera Tracker Camera from After Effects.

Have a good one.


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