View Full Version : parent/orient constraint jumping

05 May 2008, 05:00 PM
i have a serious problem with my constraint objects on the subframes. maya updates the resulting rotation of my parent or orient constraint and somehow "cleans" it afterwards. which results in invisible rotation jumps from frame to frame. it's no problem as long as i'm not rendering with motion blur - but that's what i want to.
i think it's a matrix to euler rotation conversion problem.
btw.: it's not a thing which is possible to clean up by a script (bake and change values if they jump).
any ideas how to get rid of that?

ps: i've attached a small testfile with that problem. if you'd like to use a little script source that:

polySphere -r 1 -sx 20 -sy 20 -ax 0 1 0 -cuv 2 -ch 1;
spaceLocator -p 0 0 0;
move -r 3.12531 3.219324 -2.319129;
select -cl;
select -r pSphere1 ;
select -tgl locator1 ;
parentConstraint -mo -weight 1;
expression -s "pSphere1.rotateX=frame*5;\r\npSphere1.rotateY=frame*2.5;\r\npSphere1.rotateZ=frame*7.5;";
select -r locator1 ;
bakeResults -simulation true -t "1:100" -sampleBy 1 -disableImplicitControl true -preserveOutsideKeys true -sparseAnimCurveBake false -at "tx" -at "ty" -at "tz" -at "rx" -at "ry" -at "rz" locator1;

and check the graph editor at frame 36. (the animation is baked to make it more obvious)

05 May 2008, 09:27 AM
So a little update: I discovered that problem when baking (rigid) animation and exporting to houdini via FBX.
If I import the resulting fbx-file back into Maya (or even Max) the curves don't jump anymore. Everything is clean. If I do the same in Houdini the curves jump. So our workaround is to export from Maya - reimport to Maya - export again from Maya and import the fixed file into Houdini.
What stays is the question what Mental Ray is doing when rendering with motion blur...

06 June 2008, 06:00 PM
I ran into this recently as well, what helped me out was to bake the animation with a sample of .1 and then apply a euler filter to the curves before exporting as an FBX. Then I wasn't getting anything weird on the subframes. The only downside is that the files can get heavy. But that's the price you pay for exporting animation curves from one package to another.. :(


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06 June 2008, 06:00 PM
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