Maya2Ogre skeletal animation distortion

Elusive Pete · Post by **Elusive Pete** » Tue Jun 27, 2006 11:22 am

Hi folks,

I'm a programmer on our team, and I'm trying to allow our artists to create animated models in Maya 7.0 and export them to an Ogre-compatible format. With some tweaking, I've got most of it to work. However, I'm getting some problems with certain aspects of the animation.

Some joints are moving in rather strange ways, causing the upper arms and upper legs of the character to stretch and bend in very unrealistic ways. Our artist is using a complex skeleton, which includes various controllers and IK handles, amongst other things (which I don't fully understand). The skeleton is also divided into sections, with each leg and each arm being separate from (but parented to) the main body skeleton. Perhaps the parenting relationship there could be a problem?

We've setup and are using the bind pose properly, and I've tried baking the whole animation. However, we're still getting some distortions. We're at a point now where we can't afford to spend much time on this, so it may just be a case of significantly simplifying the skeleton. I'm just wondering if anybody has encountered problems like this before?

I'm sorry I can't provide any screen shots, although you'd really need to see the animation to appreciate the problem anyway.

Many thanks.

Bringer of Darkness · Post by **Bringer of Darkness** » Tue Jun 27, 2006 1:47 pm

I believe the only thing you need is to bake up the animations in Maya and export it afterwards.

Basically, you shouldn't get this problem, I have been receiving similar problems, but somehow it dissapeared with the new version of exporter.

I am just trying to port the new exporter, so perhaps the problem is back as there were a significant changes within the exporter as I have noticed.
I will report, if something appears...

Elusive Pete · Post by **Elusive Pete** » Tue Jun 27, 2006 6:06 pm

I tried baking the animation until it was (virtually) black and crispy, but it didn't seem to make any difference. Even removing all the IK etc., leaving just the FK skeleton after baking, doesn't seem to help. It looks kind of like some of the bones are just stretching in a weird way, but it's hard to tell.

We've been trying out some simpler skeletons, and getting some promising results, so it looks like it may just have been the complexity that was the trouble.

Thanks anyway.

Joshua · Post by **Joshua** » Wed Jun 28, 2006 12:46 am

If there is a problem with exporting complex skeletons I don't think we should blow it off.

Elusive Pete · Post by **Elusive Pete** » Wed Jun 28, 2006 2:18 pm

This particular skeleton was *very* complex... far more than is normally used in games anyway, and probably more than most other real-time graphics applications (we have since found out that the artist/animator in question, who is otherwise extremely good, has never worked on games before -- the only limitation he knew of was the poly-count).

Basically, there were multiple joints making up each limb, with some bones extending backwards over the other joints (for purposes of more realistic constraints, I expect). Given the rather odd ways in which Maya silently buries things in its scene graph, it's also quite possible that some weird (and unexported) transformation was being applied somewhere.

I think the moral of the story is this: start simple, and work up from there.