Basically I want an interactive version of

With a rise of easy access to physics engines, I’m thinking about what sort of techniques we can use to simulate such things.

If I remember correctly, Kilif was working on some physics tools at one point or another (I loosely remember some .gifs of wobbling connected vertices?). I imagine soft-body physics is pretty hard to do well, but he’d be the one to ask if I’m remembering right.

That is correct, I was working on that. The thing about soft body physics is that implementing a simple soft body is pretty straight forward with a basic understanding of how to implement springs. If you’re alright with the simulation being less than accurate, then you could make something like what is being shown here with relative ease, even one with advanced 2D graphics. Extending it to 3D should further be straight forward, though more computationally complex as you can imagine.

The problem comes into making it dynamic. What, specifically, I was working on was a system that allowed for fat to be gained and a physical simulation of how that would look and interact with outside forces at any weight. The goal was that by making such a system, I wouldn’t need to guess on how a given person would look each step of the way as they gained weight, but rather the simulation would figure that out.

This introduces a swath of new problems, the biggest being soft body collisions, which is a considerably more difficult problem than just implement spring physics. Ultimately, I got discouraged working on that and dropped it, since the computational complexity of it would cause most computers to chug along.

That being said, with some work adding textures, the simple spring physics I implemented would allow for a (less accurate, granted) simulation similar to what is shown here in that picture.

Doom-the-Wolf has recently added jiggle physics to his Interactive Flash games.

I was playing with dynamic meshes in Unity this summer and got this simple wobble demo working

rectangle mesh + elastic forces and simple math to calculate the dynamics