Earthworm
Film/TV

This advanced example project explores the usage of several new rigging features available in Houdini 21.

With Houdini 21, control groups consolidate several related controls together as a unit, AbstractControls are promoted into sliders, toggles, and menus, and custom python callbacks are executed in response to control events.

The earthworm rig makes use of several new features of the spline rigging nodes. The rig demonstrates how to create a fixed length joint chain rig. Pins, which connect a position on the joint chain to a position on the curve, allow for precise control over the position of the joint chain. Using a single pin, the joint chain can slide along the curve; or alternatively, multiple pins can stretch and squash the earthworm. The pins controls are configured as uvslider controls, allowing them to be dragged directly on the curve.

This example file serves as a starting point for creating complex, flexible, and dynamically configurable rigging setups.

(4 responses)

Asset Type
Character Rig | RIG
Published
Sept. 30, 2025
Terms of Use
Standard License
Created in
Houdini 21
Categories
Rigging
DOWNLOAD RIG [194.0 KB]

COMMENTS

  • AlessiaHoudini 3 months, 2 weeks ago  | 

    This is why I love side fx and Houdini, I'm literally in the middle of my last year of studies and i m researching for how to make rigs in Houdini and this literally just got posted. Thank you man.

    • maitlandvt 3 months, 1 week ago  | 

      I feel the same way.. i was just about to rig a witch's broom, check the content library and low-and behold...!

  • maitlandvt 3 months, 1 week ago  | 

    My first thought was:

    This is EXTREMELY fun to play with in the viewport.


    My second thought was:

    I wonder how i can record myself playing with it in the viewport?

  • phinnaeus 3 days, 5 hours ago  | 

    The CV's and pins don't update above 4

  • phinnaeus 2 days, 1 hour ago  | 

    Hi Bradley, thanks for this!

    I'm looking to rig a snake for a personal project and this seems to be a good base to start from.

    I have a Brown Snake model I have created in Zbrush and I wanted to add a head, jaw control and retractable fangs to your rig.

    I've copied your setup and and added the extra joints in KineFX, renamed them and parented them to joint_1 , then I've painted some weights for the mouth and the fangs using paint capture and tested the deformation with a rig pose node, but then when I run it through your custom Apex auto rig component, the vex snippet is not understanding these joints as part of the rig and the parenting breaks obviously.

    Any clues how to fix this? My vex knowledge is beginner level so I'm scratching my head here!

    Thanks in advance.

    • bradleyh@sidefx.com 1 day, 14 hours ago  | 

      Hi Phinnaeus,

      This rig is an advanced example which explores various new features of the new spline nodes (like the pinning features), as well as the use of control groups, and python callbacks. I've made a number of simplifications to the rig component in order to highlight the usage of some of these features (and avoid some of the distractions of a more generic implementation). One of those simplifications is the assumption that all of the joints in the skeleton are part of the spline setup. For example, in the first few lines of the function buildCvControls(), I'm checking the point count of the skeleton and building the spline's cv controls between the first and last joint in the skeleton.

      This example can be extended, however, if you're looking for more of a plug and play option, I would suggest starting with our standard autorig components. The "Spline" component may be a good starting point for a snake rig.

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