BVH and FBX

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evengi
Posts: 47
Joined: Mon Feb 01, 2010 6:53 am
Location: Norway

BVH and FBX

Post by evengi » Mon Dec 10, 2012 5:54 am

When exporting to either BVH or FBX I`m getting unexpected results.

Performing action in Arena looks good. When ecporting this to motionbuilder as c3d and mapping it on an actor, it looks right.
But when exporting to either bvh or fbx, it seems the hip are pulling the legs up at certain situations.
In addition the skeleton seems to not follow all motions to the extremes.

Example: If the performer in Arena bends forward, the hips will pull the feet off the ground.

The example image should show identical motion.
[img:left]https://dl.dropbox.com/u/13853373/Poste ... Motion.jpg[/img]

How do I awoid this?

Thank you!
Cheers
Roger Gihlemoen
www.evengi.no

Seth Steiling
Posts: 1366
Joined: Fri Jun 27, 2008 11:29 am
Location: Corvallis, Oregon

Re: BVH and FBX

Post by Seth Steiling » Mon Dec 10, 2012 6:44 pm

Hi Roger,

I pinged one of our MoBu gurus about this. Here was his response:
These are very common issues. The C3D and FBX file should drive the actor the same way if you use rigid bodies to help with the gaps. BVH is a skeleton format and should not be used with an actor. The BVH skeleton should be characterized and used for character to character retargeting.

When retargeting from the actor to a character the characterization tools should help with some of the issues described. An animator will almost always have to touch the final animation to fix the solving and retargeting issues that just cannot be handled with the automated process.
Hope this helps!
Marketing Manager
TrackIR | OptiTrack

evengi
Posts: 47
Joined: Mon Feb 01, 2010 6:53 am
Location: Norway

Re: BVH and FBX

Post by evengi » Wed Dec 12, 2012 12:15 am

Hei Seth.

Thank you for helping out.
This will certainly sharpen my attention towards correct retargeting.

But yet, it does not answer why the fbx and bvh does not match the output from Arena before any retargeting is applied.
As of now it seems c3d is the only format offering exact match on export?


Thank you!
Cheers
Roger Gihlemoen.

Seth Steiling
Posts: 1366
Joined: Fri Jun 27, 2008 11:29 am
Location: Corvallis, Oregon

Re: BVH and FBX

Post by Seth Steiling » Wed Dec 12, 2012 11:35 am

[quote=evengi]Hei Seth.

Thank you for helping out.
This will certainly sharpen my attention towards correct retargeting.

But yet, it does not answer why the fbx and bvh does not match the output from Arena before any retargeting is applied.
As of now it seems c3d is the only format offering exact match on export?


Thank you!
Cheers
Roger Gihlemoen.[/quote]
Do you happen to have your .skl and .pt3 files from this capture still? If so, can you email them to me so we can take a look in house?

Failing that, a screen capture showing the Arena playback followed by BVH playback in MoBu might help.

If you have the files, you can send to seth[at]naturalpoint[dot]com.

In general, even outside of whatever is happening here, my personal preference is to bring C3D into MoBu instead of BVH. I like to make use of MotionBuilder's skeleton solver, which is quite powerful.
Marketing Manager
TrackIR | OptiTrack

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