Rigging a Scorpion Mech: Part Five, Messing with the legs

I’ve now made further progress in rigging the legs. For the limbs, I’m implementing an IK/FK setup. My approach for setting up the switch is a twist on the standard 3-bone setup where the original joint chain is duplicated and influenced by two separate chains.

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Rigging a Scorpion Mech: Part Four, Progress on Proxy Model

Reduced model to about 12k polys. The original model is about 330k.

Positing a minor update. With the rig completed for the spine and tail, today I mostly focused on creating a proxy mesh for the newly rigged areas. A handy tool I like to use when building proxy models is zooSurgeon. This neat script takes a skinned mesh, breaks it down to solid segments, and constrains the segments to influencing joints. I incorporate this script in my workflow by first skinning the reduced mesh using solid weights (one joint per vertex), and then running the script to get my true proxy. For me, this is efficient because I can preview the behavior of the proxy prior to breaking down the model.

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Cat Rig

Le Purrrrrrr

I did this quadruped rig as a freelancer for Mondo Studios.  The cat uses IK for the legs and a spline IK for the spine. Achieving the feline’s seated position required both careful weighting and some corrective blendshapes around the hindquarters.

Postmortem: Rigging Chopsticks and Characters for a Short

This was an animated short I contributed to  as a freelancer in 2007; and after an almost 2-year hiatus, wrapped up in late-2009. The two characters were modeled by Shon Mitchell, and animations were done by our client, Jonali  Bhattacharyya. This was a fun project that involved rigging two bipeds with the added twist of making them capable of wielding chopsticks. Jonali was really great to work with, and communicated her needs well. I’ll go into some detail about the Maya rigs created and the accompanying MEL tools used by the animator.

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In part three of my scorpion rig series, I went into some detail of how I make a spline IK stretchy. The approach is something I’ve used for a while and I’ve made a Python script a while back to automate the process. Today, I wish to share that script with the world! How it works is that it takes the specified Spline IK,  builds the nodes, and connects the network together to make a stretchy system. You can download it here; give it a try, and feel free to post any feedback!

Download sasStretchySpline

Bat Rig

A bat rig I did at Massive Black for use in an animation lecture. The bat features IK/FK switching on the arms and legs and some extra layers of control to deal with gimbal locking. The wings were quite fun to skin in a masochistic sort of way. The bat was modeled by Shon Mitchell and animated by Chris Hatala.

UPDATE: here’s the flight cycle, animation by Chris Hatala.

Rigging a Scorpion Mech: Part One, Prepping the Model

I thought it be interesting to document my rigging process from start to finish using a fairly challenging model. I’m not going to push this series of tutorials as an “ideal” way to rig such a machination, but it will show one approach. I’m going to rig a scorpion model I came across in the forums of CGTalk (original post here). The artist, Nicholas Silveira, modeled and rigged the creature and was nice enough to share the bare model to give anyone else the oppurtunity to rig his creation.

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Vertex Weighting Tool for Maya


Download python script for Maya

The Weight Tool is a Python script designed to make your skinning life easier. It streamlines the process of manpulating skin weights on the vertex level with a neat UI. I came up with the idea of making this tool after skinning some rigs in 3dsMax. The result is a script that works very similar to 3dsMax’s built-in Weight Tool, but in Maya now!


Like any python script, this will only work in Maya 8.5 or later regardless of OS (tested only on Windows). To use the script in Maya, simply copy all the scripts from the archive into your PYTHONPATH. Once copied, restart Maya and type “import WeightToolInterface” in the python command line. To start using the tool after importing, type “WeightToolInterface.draw()” in the same commandline/scriptEditor.

*Note that you can find your PYTHONPATH by opening your Maya.env file with a text editor (usu. located in …/My Documents/maya/versionNo/Maya.env). If PYTHONPATH is defined, simply copy the scripts and continue from there.If PYTHONPATH is NOT defined, type in the Maya.env, “PYTHONPATH=C:/your/script/path/here”, replacing C:/your/script/path/here with a real system path you wish to install Python scripts to. When editing Maya.env, be sure to restart Maya to apply any changes.

Feel free to post any feedback!