Importing and using skeletal animations

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Hi, I have a few question regarding FBX animation import and usage in Houdini.

1. Let's say I have a mesh skinned to a skeleton and I also have a couple of animation takes for that skeleton. These animations, however, are stored in a separate FBX file with only bones, no mesh. I import the mesh and the animation and what I get are two separate networks. What should I do to import animation to already imported bones?

2. After importing a skeleton to Houdini, I get a strange bone structure with empty transforms above every bone. Is it normal behavior? Does Houdini separate a bone deformer and its transform node?

3. How do I blend two animation takes together into a sequence? You don't need to describe the process, just name the tools and I'll find it.
Edited by n2e - Aug. 24, 2020 23:40:17
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Hi, anonymous user,

you are not giving any context about what you mean by “importing a skeleton” - this could be importing a Houdini scene file (which you would have all the answers about that you are looking for), an FBX or anything else. Depending on WHAT you mean by “importing”, these thoughts might be helpful:

1) you could write a script that copies/links your deformed mesh's skeleton's bones to your imported bones. If you have a naming match, that script would be pretty straight forward.

2) without an example I find this hard to understand. If you import a scene you created yourself, you are the only one who can tell what “empty transforms” you have placed where. If, however, you are importing an FBX, what you are describing is the “joints based rig versus bones based rig” issue that I have discussed in detail in my thread about “converting joints based rigs to bones based rigs” in the “third party” part of this forum. Bascially, what you want to do is recreate the rig based on the joints (nulls) weights but using Houdini bones. Or you implement a workflow that uses joints INSTEAD of bones.

3) I am not clear about what you mean by “sequence”. Blending animations would be simple if you followed the idea outlined in 1), binding your deform mesh to the animated skeleton, you could use a global float value that would specify the amount of the various animated skeletons' input for the “final output” on your deformed mesh.


Marc
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Out of here. Being called a dick after having supported Houdini users for years is over my paygrade.
I will work for money, but NOT for "you have to provide people with free products" Indie-artists.
Good bye.
https://www.marc-albrecht.de [www.marc-albrecht.de]
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Yes, I was talking about an FBX scene, I forgot to mention that.

3) By sequence I mean a single animation consisting of many simpler ones, like walking forward, then turning right, then walking again. The thing you would typically accomplish using NLA editors in other programs, like Maya and Motionbuilder.
Edited by n2e - Aug. 24, 2020 23:51:50
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Well, what I said above - alternatively, with H18 you could have a look at the Crowd Animation system in Houdini.


Marc
---
Out of here. Being called a dick after having supported Houdini users for years is over my paygrade.
I will work for money, but NOT for "you have to provide people with free products" Indie-artists.
Good bye.
https://www.marc-albrecht.de [www.marc-albrecht.de]
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