Modular Rigging

So starting to think about modular rigging, discussed on the CGTalk forum. The basic process for this I’m thinking about is having a common  skeleton (player, creature, etc) where its used as a template  to build an animation skeleton.  Animation data can get baked down on to the skeleton, or mapped up from the skeleton. And the skeleton itself can be used for generating FBX, mocap, etc

This sounds pretty common, but Im just starting to see the benefit of it. Alongside this ILM’s block rigging paradigm could be used for the animation skeleton- rigging blocks for legs, feet hands plug-n-played for different shots, scenes etc. Some remits:

Common template skeleton

• Must have a non-broken hierarchy, including end (nub) bones.
• Must use a common coordinate system throughout.
• Must have a common naming convention throughout

Animation Skeleton

• Rigging blocks can be created in isolation.
• They return outputs/inputs to allow other blocks to connect to them.
• They can be removed easily without ill affect on other blocks.
• They have common attributes that can be shared.
• They can be traversed easily, back to a common ‘grandfather’.
• Optional: A common markup language for there creation, XML etc.

A meta-data paradigm for rigging.

I was reading up on Bungie’s modular rigging and ILM’s block party – they talk about modular nodes that define how the character is made and built. I think it’s a great system to use and I’m still trying to get my head around it!

My aproach is to treat the system as searchable properties with values. Nodes with assigned properties can be then rigged based apon them e.g a bone may have a property called, “left”, “leg”. And have sockets and plugs (ala ILM) to tell it how to be rigged.

My only problem is that how are properties different to each other to be meaningful? I.e we can rig a leg it different ways – how does it know which way to use? It may be just another simple tag like “basic’ or ‘dynamic’ but im not sure.

Bone:Left:Leg:IKFK? – maybe its this simple?

Also, do we need attribute headers i.e properties – “Type”, “Description” etc or just the values themselves, “left”, “arm”, “IK” ? Personally I think you have to have properties as firstly not everything should be a string and secondly most importantly how do you differentiate between numerical values of 2 or more properties? e.g TYPE:2  LOD:2 now two values of  2 are essentially meaningless, unless they have some identifier.

I’m going to pursue  this further as i think its definitely the way forward.