Rune Skovbo Johansen
Creative Programmer & Designer


Adaptive Animation for Character Locomotion

Mar 4, 2008 in ,
I have just begun working on my Master Thesis, which I will be making in collaboration with the company Unity Technologies that make the awesome Unity game engine.

The Master thesis will be about "Adaptive Animation for Character Locomotion", which basically means creating a system for adapting walking, running, and crawling keyframed animations to a dynamic environment. The system will take curved paths, uneven terrain, and variable speed into account all the while ensuring graceful footsteps without slipping feet and motions that stay as faithful as possible to the original keyframed animations under the given restraints. Inverse kinematics is one of many techniques that will be involved in this.

Goals and perspectives
The system is meant to be generic in nature, working not just for biped characters (with two legs) but also for example for dogs, bugs, and spiders and, say, robots and aliens, provided that they move around using a limited number of legs. This list of features is the ideal case - time will tell how far I get within the timeframe of my Master Thesis. Hopefully I can continue working on the project after my graduation, if necessary.

In the end, the result of my work will be made available to all users of Unity free of charge, for any use. I hope to get people from the Unity user community involved in testing the system as it is developed, since one important success criteria is the usefulness and usability as perceived by the developers using the system. It will take some time before the first prototype is ready though, as I've only just begun.

The project up until now
My original "pitch" of the project to Unity was a presentation based on this slideshow:
See PowerPoint slidehow

A few ideas have already changed since that. For one thing, the idea that animators must enrich the animation cycles with additional data has been abandoned. The data needed is for example information about when exactly each foot leaves the ground and land on the ground again. The new plan is that this will be automatically analyzed and calculated by the system. More on that in a later post.

In order to quickly get my feet wet, I've made this little demo, where I have modified the Goober guy that comes with one of the Unity tutorials, and made his legs use some very simple inverse kinematics:

Click the image to make the demo run in the browser. Just click yes to install the Unity browser plug-in. Note that in this simple demo I simply adjusted the altitudes of the feet, so feet slippage etc. are not prevented. The actual system will work in a completely different way.

I have already gotten some interest and positive feedback in the Unity forums. Stay tuned!

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