KineFX/APEX Example of Bones Animating Along A Curve Request

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hello.

I'm learning how to rig a porpoise using KineFX/APEX.
I want to rig it so that the body follows a curve in the shape of a sine wave, to mimic the porpoise "porpoising" repeatedly in and out of the water.
Here is video reference of the swimming behavior I want to mimic:
https://youtu.be/Y6SFPsRfSRA?si=w0rYgXskxCe37B6C [youtu.be]

I found this ancient Houdini snake rig tutorial that shows the functionality I'm looking for.
https://youtu.be/Eo6Lue1TMZU?si=-EILM4iKgUK5zkim [youtu.be]
Can someone point me to an example of how to do this in KineFX/APEX? 🙏🏽

Thanks
Edited by syntheticperson - Sept. 4, 2024 23:52:57

Attachments:
Porpoise_KineFX_rig.png (3.5 MB)
HoudiniSnakeRigFollowingCurve.png (1.0 MB)

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The content library might cover your needs:

https://www.sidefx.com/contentlibrary/character-switching/ [www.sidefx.com]

https://www.sidefx.com/contentlibrary/elephant-trunk-sine-wave/ [www.sidefx.com]

https://www.sidefx.com/contentlibrary/kinefxapex-workflow/ [www.sidefx.com]

https://www.sidefx.com/contentlibrary/elephant-seal-fem/ [www.sidefx.com]
Edited by PHENOMDESIGN - Sept. 8, 2024 21:50:23
PHENOM(enological) DESIGN;
Experimental phenomenology (study of experience) is a category of philosophy evidencing intentional variations of subjective human experiencing where both the independent and dependent variable are phenomenological. Lundh 2020
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PHENOMDESIGN
The content library might cover your needs:

https://www.sidefx.com/contentlibrary/character-switching/ [www.sidefx.com]

https://www.sidefx.com/contentlibrary/elephant-trunk-sine-wave/ [www.sidefx.com]

https://www.sidefx.com/contentlibrary/kinefxapex-workflow/ [www.sidefx.com]

https://www.sidefx.com/contentlibrary/elephant-seal-fem/ [www.sidefx.com]

Hi PHENOMDESIGN, thanks for the suggested examples. I'll check them out.
Edited by syntheticperson - Sept. 9, 2024 00:46:20
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For something like the snake, you can also try using the rig::CurveConstraint node that allows you to create transforms constrained to a curve at a particular u value.
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edward
For something like the snake, you can also try using the rig::CurveConstraint node that allows you to create transforms constrained to a curve at a particular u value.
Thanks, Edward.
However, the documentation for the APEX curve constraint is sparse:
http://127.0.0.1:48626/nodes/apex/rig--CurveConstraint [127.0.0.1]

It would be helpful if someone could point me to an example of the usage of this function.

The other challenge is that I would need to constrain each joint along the spine of the porpoise to the curve.
This means I would need to calculate the distance along the curve as a U value based on the distance between the joints along the porpoise's spine.
Does anyone have any examples of how to do that?
Thanks
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Hopefully this helps, Its a simple script that calculates the offsets and makes sure that the scale stays consistent.
Edited by william_harley - Sept. 23, 2024 03:31:46

Attachments:
path_constraint.hip (397.8 KB)
pathconstraint.gif (1.1 MB)

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william_harley
Hopefully this helps, Its a simple script that gets calculates the offsets and makes sure that the scale stays consistent.
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Hi william_harley. This is very insightful!
Many thanks!
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