there are a few methods out there creating an upper arm roll, however, none of those methods work in all possible situations, so it’s quite normal you will have to switch to one of 2 solutions (like backwards and forward arm or something like this). if you actually animating and come to this area you have a problem…

so for my diploma thesis i came up with the following method i like to share with you.

1. You will need an upper arm with at least 2 joints, better 3 or 4 to give a nice volume preservation. Then you will need also a driver arm setup for the ik with just 2 bones. The chains must have the same LRA-Orientation for this setup to work.

   

2. Create a rotate-plane ik fort he ik-joints. This will be a simple arm-setup to later drive the deform joints.
3. Now comes the funky part…
   Create another rotate-plane ik for the first deform joint, set the polevector of the rotate-plane ik to 0-0-0. By doing this the ik will „remember“ it’s orientation and will ony flip if the ik-handle gets to the exact opposite. This trick will ensure the the first deform joint will not self-rotate, it will always keep it’s original orientation. This ik-setup acts a little bit like a aim-constraint.
   
   
   
   
4. Now parent the rp-ik to the first upper-arm joint from the driver ik-chain. By doing the deform-chain will follow the driver-chain without doing the self-rotation. And thats exactly what we wanted: NO SELF ROTATION !!!
5. The next step is, you guessed it, to apply the exact self-rotation or roll-difference gradually back to next 3 joints of the deform chain. To measure this difference we create a locator, which we parent under the non-self-rotating first deform-joint. Then we create an orient constraint from the first driver-ik-joint to the locator. This way the locator rotates with driver-chain, but since its parented to the deform-chain, which also rotates with the driver, except for the roll-component, you get the exact rotation difference.

   

6. The last step is take the rotate value of the locator and divide it through the number of deform-joint – 1 and connect this value to the defrom-joints self-rotation.

   

7. The Setup is finished. You will see it produces very stable results. It will never flip unless the arm is positioned to the opposite, which is for more or less every character impossible.

Hope you liked the Tutorial!

cheers,
tom

download shotlist + cv

.: the anatomical rig :.

This video shows the results of my diploma thesis at the University of applied Sciences in Salzburg/Austria.

Optimization and reduction of the
human skeletal system for 3d-animation

The research was to find out if a rig, which is completly based on human skeletal
anatomy can produce better deformation and also animation results than normal
standard rigs do. So the rig was built to be as anatomically correct as possible on
one hand, while maintaining easy to use and intuitve manipulation controls on the
other hand.

The main features:

* as anatomically correct as possible and reasonable (with maya’s standard feature set)
* anatomical correct placement and behavior of all bodyparts
* anatomical dependencies throughout the spine, shoulder and hip
* anatomical limits on all joints
* fk-based spine-setup with additional ik-spline like controls
(because with a spline-ik, joints can not be exactly controlled)
* anatomically correct chest rig with breathe control
* fully automated clavicle and scapula
* stable shoulderjoint self-rotation elimination in all possible poses
* stable wrist-setup
* automatic pole-vectors for arms and legs, so are in the expected
positions most of the time
* anatomically correct foot-setup with reverse-foot like controls
* anatomically correct jaw setup
* fully joint-based, no use of extra deformation techniques
to be comparable with standard-setups
* fully node-based, no expressions

The results:

The resulting deformation of the rig reaches a high level without using any extra
deformation techniques like corrective-blendshapes. The anatomical limits on
almost any joint leads keeps the rig in anatomical space and leads to some really
natural looking motions. As a “side-effect” of the limits on the joints but not on the
control-objects the motion is distributed to next bodypart when the previouse one
reached its limit, which looks very pleasing.

So being as anatomically correct in placement and behavior of the joints leads to
very good deformations. Building anatomical dependcies between bodyparts and
limiting all joints results in very natural motions while always being in a correct
anatomical space.

main focus
physically correct looking car rig with most control for the user

[Show as slideshow]

main focus
creating intuitive quadruped character rig for interaction with dynamics

[Show as slideshow]

download highres picutre (1 mb)

advanced
Maya mel, Pixologic ZBrush, Maxon Bodypaint3D

basic
Alias Motionbuilder, Eyeon Digital Fusion, Maxon Cinema4d

programming
Maya mel & expressions
basic C++

other software
Adobe Premiere, Adobe Illustrator, Virtools Dev,
Steinberg Cubse, Steinberg Wavelab, Native Instruments Reaktor,

contra
perfectionist, drinking too much coffee;

visiting lecturer for Rigging in Maya @ FH Salzburg

freelancer @ FreshFX Media