Just a side note on some of the technical problems with customising 3D models in a game engine. The main problem is, if you were to have a skinned model/biped and you make changes in the engine, to the bones for example…think ‘big head mode cheats in the ninties’. The animation will generally snap everything back to the default scale, rotation and local position when it plays.

The second problem is scaling one bone scales the next bone due to the IK chain set up so you’d have to solve that with some fancy scripting.
(by no means a solution)
Unity Script ———— gameObject.SetActiveRecursively(true);

Something like this would allow you to scale along the IK chain through each object/bone i believe…

There is plenty of research in this field though and there is also the possibility of using procedural animation as well. Some light reading links on the subject below….

[button url=”http://cs.gmu.edu/~ygingold/rigmesh/rigmesh-small.pdf” align=”center” color=”black” width=”half” ]Automatic Rigging for Part-Based Shape Modeling and Deformation[/button]

[button url=”http://aigamedev.com/open/article/planting-the-spores-of-procedural-animation/” align=”center” color=”black” width=”half” ]Planting the Spores of Procedural Animation?[/button]

[button url=”http://chrishecker.com/images/c/cb/Sporeanim-siggraph08.pdf” align=”center” color=”black” width=”half” ]Real-time Motion Retargeting to Highly Varied User-Created Morphologies[/button]

The good news though is unity4 is coming with an animation retargeting system (Mecanim) which could make things easier. Other solutions are the third party procedural ones like ‘mixamo’.

Image 1 is my test scene for bone scaling a skinned biped with retargeted animation and 3ds max animation. Does not work! Using ‘mixamo’ it can’t be retargeted in realtime either so you’d need an alternative automatic rigging animation system.