[A.R.T] Error while applying Mocap Data in ART

Development Character & Animation
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1

Hi,

when using the Import Animation feature in A.R.T. I get the following error after importing a FBX file:

Error: Cannot delete ‘SampleChar:auto_hips_knee_loc_l’ as it has locked or read-only children.

Error: Cannot delete ‘SampleChar:auto_hips_knee_loc_r’ as it has locked or read-only children.

Exporting a motion to FBX from that character works, but if I use animations from different character the import Mocap won’t work.

2

Hi there!

I’ve been trying to reproduce this, but no luck yet. First, do you have the latest code drops from the master thread here?:
[Master Thread][1]

Another thing that would be helpful is if you could turn on ‘show stack trace’ and ‘show line numbers’ in the script editor:

4049-clipboard01.jpg

It will be easier to track down where in the code this issue might be coming up for you. As a test, I exported a simple 2 pose animation on a character using the export fbx tool in export motion. Then in a new scene, I added that character again, and imported the mocap, using ‘both’ and turning on both solvers for knee and foot roll. I couldn’t get a repro, even trying to import onto different characters like you suggested.

3

Hi Jeremy,

thanks for your response. I am using the latest code.

As a test, I exported a simple 2 pose animation on a character using the export fbx tool in export motion. Then in a new scene, I added that character again, and imported the mocap, using ‘both’ and turning on both solvers for knee and foot roll

This is working for me, too.

However, if I want to use an animation from a different character with a different skeleton the error shows up.

I’ve attachedlink text the error log.

4

Yeah I tried as well importing onto different skeletons (different spine bone counts, finger bone counts, etc) and still no issues. I take it both characters were created with the tool? Any chance of getting the FBX file? You can email it to me at jeremy.ernst@epicgames.com if you don’t want to attach it here.

Thanks!

5

Send you a mail with the fbx.

6

Thank you for the files! I see the issue now that I can see the fbx being imported.
The FBX looks like it is from a Max biped skeleton. Any mocap imported onto a character needs to have been created with the tool. Essentially, it needs to have the same base skeleton/naming.

What you would need to do is retarget your skeleton motion from the biped skeleton onto your new character. This is not the same thing as importing motion/motion capture. Currently, the biped skeleton’s scale is massive compared to the Sample Character’s scale. That would need to also be addressed in the retargeting phase. MotionBuilder is the primary app people use for retargeting motions. Maya has some basic retargeting functionality as well. You just need some way to remap your motion to the new skeleton.

You might also consider bringing an FBX of your new skeleton back into Max, and transferring the motion there. Once your motion is transferred, then it can be imported onto the rig for further editing/sharing.

Here is our motion pipeline and probably the pipeline similar to most studios.
Create the character rig/skeleton. Hand that off to the motion capture guys. They do a shoot, and retarget the motion onto the character’s skeleton. Animators can then import that FBX onto the rig for editing and polish.

Hope that clears up some things!

7

Yes, this clears things up :wink: Thank you!