Eggroll setup update

I meant to post this for a while, but never got around to finish a demo of it. Inspired by Mike Best's eggroll setup, I wanted to do a similar setup because it was a good challenge. After my previously failed attempt I switched to a special matrix(found from google) to calculate rotation of the object around an axis using maya expression. This worked very well and I finally got the rolling working. However I still had some minor problem with small offset from the ground in some positions, it might be the pivot location that might be off. But more challenging is the sliding problem, though it's not very noticeable in the demo. I would like to come back to it later. Deformation of the egg should not be difficult to add to this setup as I am already counting in the bounding box volume in nodes calculation.

Later Mike was kind enough to share the script which gave me insight into his setup. Mine is not as good as his, but I was happy to get the egg rolling :)

This challenge sparked my interest in rigid body simulation. Hopefully in the future I will be able to take time into reading more about it (and begin to understand something!) to write my own little simulator. I am looking particularly for a real egg rolling simulation where the center of mass of rigid body is shifting based on the properties of the fluid (egg yolk and egg white).

Animatable Pivot System

This is a working demo of my solution for animatable pivot in Maya. I believe it is quite flexible and fast. It allows animators to shift pivots very easily and only one object needs to be keyed. No adjacent two key mechanism necessary, but you can do it if you want.

Most of the logic is implemented using Node network. There is one sctiptJob for each pivot which calls a function. This function is very small and common for all pivots hence no multiple expressions. And the only thing this mel function does is to add the value to the offset to create a new offset which then can be keyed. So there is very minimal mel footprint. All the calculations including matrix multiplication, finding how much object will move, calculate temporary offset etc are done via nodes. I should probably make a single node out of this later.

I will post a video showing the usage of this method.