I've come across an issue with the files that are exported from iPi Mocap Studio. There are random rotations on the hip in x and z which cause the whole body to pivot around the hips over a few frames. I've attached an image which shows the graph and I've overlayed the skeleton so you can see how much the whole body shifts over a few frames. If I scrub through the same frame range in Mocap Studio, I do not see the feet or hips move like they do in the exported file.
It may not look like much here, but when I retarget the animation to a character it's very noticable and takes a lot of work to remove. I've tried a gimbal filter, but that does not work. I've exported as a bvh and an fbx, but both are the same.
Any ideas what may be causing this and how to prevent it from happening?
Thanks!

This effect is caused by gimbal lock, which is intrinsic deficiency of Euler angle's coordinate system.
Here's a good video explanation about gimbal lock: http://www.youtube.com/watch?v=zc8b2Jo7mno

In your case gimbal lock occurs in Euler angle's system used in FBX. But in BVH uses another system, where I do not see this effect. Please try export / import via BVH.

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iPi Soft

Thanks, Pavel. The bvh file does work better than the fbx. I could not get the bvh to open correctly in motionbuilder, but once I figured that out I see that it does not have the gimbal issues that the fbx file has.
Thanks again!

There area a couple of different .bvh formats you can export from iPi Mocap Studio--be sure to use the Motion Builder version of .bvh. I recall running into a problem in the past with the other (generic?) .bvh format but for me the the MB-specific version imports to Motion Builder without error.

G.

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Greenlaw
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