Doodles

Update: 19 July 2008

Working with expressions recently had given me the idea of a way to automate a many legged creature walking in lock-step. Here's a sample of my first attempt, a 100 legged centipede:

The basic concept is sound, each leg follows two main expressions, one to sweep the leg back and forth, the other to raise the leg forward in the dragging motion. The rate is driven from the movement of the master ring in the front of the joint chain. A simple splineIK chain is setup along the spine, with dynamics applied to the clusters to drag the creature forward. This type of setup would be sufficient for a background character, but I want something more controllable. This would make a great milipede.

Update: 29 July 2008

Next, I wanted to make a rig that did not have to constantly be moving forward for the effect to be present, to allow the creature to stop and smell the roses as it were.

I decided to first concentrate on one segment of the creature's body, (thorax? is that the word I'm looking for?) Here's a pic of what I'm talking about:

The idea in mind is to have a series of segments, independent of each other, that can move and rotate in sequence or parallel depending on the situation. Expressions could still work here, and I'm probably going to integrate expressions in the end anyways, but my first thought here was to employ SDK. Here's what the rig looks like inside one segment:

The joint chain consists of a simple spine, plus two matching legs plus hip joints. Instead of utilizing expressions to move the legs forward, IK will drive it instead. The cube above the rig is holding the SDK channels that will move the rig forward.

Here's the rig in motion, with and without stand-in geometry :

The undulation motion is effective, and I've observed that when the left and right legs are slightly offset in time the effect comes across much more effectively, (see the first millipede like example). I tried compacting the segments together to see if there was a noticable change of undulation and added a quick head for comparison:

Discovery: full creature rotation is dependent on segment length, quantity, and stride. I was able to add the ability for the rig to turn, but as it is currently setup it cannot 'turn on a dime' automatically without hand animtion applied, so far I've been try to limit the inputs to expressions and SDK. As the rig is built now it can turn in any direction, stop, lift up, but only the ability to walk forward or backward smoothly with slight turns is completed automated.

This got me thinking again about my 1st attempt, the millipede rig. The millipede rig felt so much creepier as just a joint system. Here it is again, now with turning goodness:

Mmmmmm.... creepy, let's play with this some more!