Taken from Case 173397
Reproduced in Support team by Rampa

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Initial Problem description:
I have a smooth, good capture from Axis Neuron which loads into 3dXchange 7.6.3619.1 and plays back just fine, however when I map it to a Maya IK the result is jerky and twitchy, and basically unusable. It's a show-stopper for me and I'm sure it's not supposed to be happening.

This occurs with every BVH I've exported from Axis Neuron, every time. I have tried different ways of exporting it, but as it plays smoothly in 3DXchange before any processing I'm sure its a) good data and b) 3DXchange can clearly read it in and handle it correctly. I ensure there is a T-Pose in the first frame and I've tried loading different ones. While this changes the capture, it still remains smooth so I don't think the T-Pose is the issue, it shouldn't be able to make things choppy and jerky.

I've got the MotionLive plugin for iClone as well and that behaves the same way when I play back in Axis Neuron and record in iClone - I get the same jerky hip bone movement etc.

I have followed this tutorial:
https://www.youtube.com/watch?v=T7TWsryYjYg
And the results that the presenter gets, in both the realtime and the conversion via 3dxchange are very different to what I'm experiencing. I would dearly like to achieve the results he is seeing.

Find a video demonstrating the problem here:
https://youtu.be/BI4aIW2Sllk

The source mocap from Axis Neuron is attached as "gen walking 1.zip" for repro purposes

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**Workaround**
I have found a workaround by trying many different things. The workaround is this:

Import BVH into 3DX
Export the file as a BVH from 3DX
Import the 3DX exported file back into 3DX
Convert to nonstandard character as per tutorial/normal workflow

The conversion remains perfectly smooth now, with no jerkiness.

You can read BVH files with a normal text editor and the structure is very different between the Axis file and the exported 3DX file. It shows that 3DX needs to transform a BVH into a different format to handle it properly, but also it shows that it *can* do it and probably should be doing it in-memory rather than needing the import-export-import manual steps.

The knock-on effect of this of course is not just an annoying manual process, but also that this in-memory transformation stage is missing with the MotionLive plugin from Axis Neuron to iClone, meaning that entire (_paid-for_) plugin is rendered useless as the motion data is corrupted.