Developer Notes

Volumes, Bones and Appearance Sliders

On 17-Oct-2023 Ada Radius made some notes on the relationship between bones, volumes, slides, etc. One day these might be useful 🙂 …

I built Max specifically to the LL avatar definitions, the xml files, only with a better topology than the LL llm data. If we stay within those limitations, we won't have arm length, eye position and quite a few other anatomical criteria the way an artist would want them, but the body will work with the Appearance sliders. I published all this information at the New Media Arts HitHub so our research is out there. In the form of spreadsheets, mostly. Making a mesh body so it works

The volumes (they’re not really bones) don’t do good deformations, because they’re not meant to do deformations at all. They were originally included in the avatar definitions to keep avatars from walking through each other. The system avatar primarily uses mesh morphs to change shape in the sliders, with only a few armature parameters. Mesh bodies share those armature settings with the system avatar, but use armature and volumes, rather than mesh morphs, in the Appearance sliders. The system avatar rigging and skinning is different than for mesh bodies, and affects how mesh bodies look. So some things never work well. That they work at all is amazing. But we do like our Appearance sliders.

I got interested in it while working on Ruth and Roth. We had been using Avastar until Blender 2.8 came out and SL made changes in the viewer. Avastar stopped working for Roth. So I started digging into the xml data to find out what was going on, figured out the arithmetic (Maya to Blender) and got an armature built in Blender shortly after that. After Kayaker Magic joined the effort I had data I could use from the llm files, which I incorporated into my proof of concept, and added to the spreadsheets. Then Tom Ernst (aka Owl Eyes) started working on how the code interfaces with the data.