Motion Capture Resources

Updated on Aug 31  2017

see also Crowds Resources


Overview



copyright  Deborah R. Fowler

Deborah R. Fowler | Houdini fbx mocap files

Deborah R. Fowler



Houdini with Mocap

Posted on April 11  2016
Updated on Feb 5  2017

Refer also to the Houdini Documentation http://www.sidefx.com/docs/houdini15.0/character/motioncapture

Using fbx motion capture data out of Vicon Blade or from Motion Builder is easy. Import the fbx. Be aware that Houdini does exactly as you tell it. You need to set the fps on your import to override your data - if you do not, it will come in as 120 fps.  You can use merge or import (import will override what is there, merge will add the fbx to your existing contents). The examples are show for an fbx from Blade. (If you were to do an fbx that had Geometry/Materials or Cameras you would change the Filter Options).

For speed, you can change the option from Every 1 frames to say 8, but be sure to override the FPS.
(NOTE THIS WOULD BE FOR PREVIS - if you need accurate data use every 1 frame.

TIP: Cleaning up your fbx in Mobu before bringing it in to Houdini will also speed up the fbx load, ie. system, unlabeled markers etc.

TIP: If for some reason you create an abc to go from Houdini to Maya with this data - don't. Okay, go ahead but be careful since fbx data is not designed to be renderable usually you will have to create the alembic, click off visibility and then create another alembic container.

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For your first exercise, to add geometry to the skeleton you can using parenting with the skeleton parts.
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Alternatively you can put them inside the nodes - you will then have to make the node renderable (it is off by default). Simply
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Missing ImageIf you forget to change the Override FBX Frame Rate, your data will come in at 120 fps (Maya converts it automatically, Houdini trusts you to change it). You can change it in the Global Animation Settings.
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However, be aware that this works correctly if you are using Every 1 frame. If you use the Override FBX Frame Rate you can use a higher frame rate and still get accurate data, however if you use say 8 and change it after the fact in the Global Animation Options it will result in a different interpretation of data as seen in the cartwheel example below.

















Image: on the left in Maya, compared on the right in Houdini
then below the image is compared with frame 8 and not overridden and changed in the animation options
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Below
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