Alembic from C4D to Maya - Not working

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  07 July 2016
Alembic from C4D to Maya - Not working


Let's keep it simple. I have a much more complicated project that's being rendered in vray on maya (also making a trip into Houdini along the way) and the alembic export from Cinema is just wrong. It's making me look bad in front of my Maya and Houdini friends here at the studio.

Simple test we've done:

I am animating a cube. 0 degrees to 720 degrees on x(h). Linear. I export that as an alembic. it looks fine in Maya and in Houdini. However when rendered in Maya the motion blur goes all whacky because in the subframes the cube is rotating on other axis. No matter how many subframes I export, or how little I uses, or even when I use none. When you scrub the subframes in Houdini you can see the cube jumping all over the place.

There is something wrong with the alembic itself out of C4d? Is there a solve for this? It's like a gimble lock Euler problem but there's no way to fix it. I need to solve this as I am the animator and it's really my problem.

Thanks for any help!
  07 July 2016
By default Cinema uses HPB rotation order... change it to stick with MAYA default, which is XYZ ...
Also for Motion Blur you can put more subframes in Alembic export...

Last edited by ugrens : 07 July 2016 at 06:44 PM.
  07 July 2016
How would I go about doing that?
  07 July 2016
Originally Posted by randmcnally: How would I go about doing that?

At the Coordinates Tab of each object on the bottom Right you can change rotation Order.
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  07 July 2016
Originally Posted by randmcnally: How would I go about doing that?

In Cinema ... Selected Object/ Attribute Editor / Coordinates(Coord.), under Rotation Fields you have Order List, to set Rotation Order...pick the XYZ and go on...
Make sure in Maya, you are using the same order XYZ ...
  07 July 2016
Alembic problems

In attributes manager under coordinates is a button to change it. Alembic even in C4D does not render MB properly with default settings (you need to bake a polygon copy of the alembic object via timeline baker).

From the help it states that the object inside of C4D is not holding the animation data but the base alembic file stored on your hard drive outside of C4D is having it. So there are no actual animation info available to the C4D's renderer it seems. Strange...
Maybe for Maya it's the same or maybe you have to export a .fbx/.obj with the .abc file which is linked to the .abc file? But I don't know if that is possible. Or relink the .fbx mesh data in Maya with tthe .abc file if possible?

  07 July 2016
Thanks for the tips guys, but this does not solve the issue. My cube that is rotating around (now on Y instead of H) still comes into Houdini and Maya with subframe issues of random rotation in the subframes causing wonky motion blur.

Any other thoughts as to why this would happen?
  07 July 2016
My suggestion is to remake animation AFTER the order is changed... Here It's working, stride forward ...
Attached abc file, exported from Cinema ...
Attached Files
File Type: zip (8.9 KB, 2 views)
  07 July 2016
You are correct. That is working. HOWEVER: Try putting that into a null and doing your animation on the Null then opening it with Houdini or Maya. That's the problem we are having. If we animate directly on the objects then it's fine. But as soon as we have a null tree we run into the problem. Appreciate the effort by the way!
  07 July 2016
Sorry, but I can't confirm your issue . I have exactly the same correct result with Null. Hm...Did you change the order for the Null ?... I guess you did ...
  07 July 2016
Yep I definitely did. Are you using r17.048?

Are you testing the clip in Houdini or Maya by chance?
  07 July 2016
Just to add my two cents, I tested the scenario you described using R17 along with Maya and Houdini. So far, I'm not able to reproduce the issue you're having, as motion blur seems to be working correctly. I'm not doing anything special, but in trying to follow your example I created a cube, parented it to a null, added a rotation on H, and exported as an Alembic with subframes set to 4. I've tested in Mantra and Arnold and everything seems to be fine. I don't have Vray, so unless the issue is specific to it?

From past experience, however, I can attest that sometimes object hierarchy can screw up how other programs interpret the rotation order. If, for example, you have a lot of nested, or parented objects, that are all keyframed, there may be an issue with precedence (they're all fighting over who rotates first).

To test this theory, take your object and instead of animating it with transforms, try binding it to a single joint and animating it that way. I know that sounds strange, but that's the only way I know to confirm whether the issue is with your scene hierarchy. If it works, then the problem is in how your objects are setup. If it still doesn't work, then it's more than likely a bug or some other limitation.
  07 July 2016
Yes, R17.048 ... imported in Maya 2016 and batch rendered with motion blur with 2D type ... MAC by the way ...
Hope you find solution ... :(
  07 July 2016
Hmmmmm weird. Will try again tomorrow. Thanks for the help. I will post if I find out what's what.
  07 July 2016
I've attached the file I animated in C4D. It's a cube spinning around. See if it works. Houdini and Maya are having subframe problems.
Attached Files
File Type: zip (4.0 KB, 8 views)
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