Esoteric software spine one skeleton multiple poses
Rotation DoFĪs with most skeleton rigs (it is even more often the case for games), the Mecanim Humanoid Rig only supports rotation animation. Note that many game skeleton rigs don’t even have a neck bone and manage to do the job with only a head bone. Considering all of this we decided to have 2 spine bones for the Humanoid Rig. Looking at a contortionist even in extreme poses clearly show this. What remains, is a main flexion point at the base of the spine and one other at the base of the rib cage. Why is this? When looking at how a human spine bends, you will notice that the part of spine that is on the rib cage is almost rigid. A third or even a forth one will only give a small contribution to the final human pose. One spine bone is clearly under defined.Īdding a second one brings you most of the way. (Note that you can always use a Generic Rig if you absolutely need this level of precision). Why 2, not 3? or an arbitrary number of spines bones? Lets discard the latest, it is not about biomedical research. We had to find a compromise between fast runtime and animation quality or openness and standard definition.
The elaboration of Mecanim Humanoid Rig and Muscle Space was confronted to some hard choices. Riggers, game companies, schools or software firms will propose their own version of what they thinks best represent the human body and motion and what will best fit their production needs.
No matter how many bones or how good your MOCAP hardware is, the result will be an approximation of the real thing. An approximation of human body and human motionĮvery new skeleton rig built for a humanoid character or any animation captured will be an approximation of the human body and human motion. Compare to standard skeleton pose, Muscle Space will always interpolate naturally between animation key frames, during state machine transition or when mixed in a blend tree.Ĭomputation-wise it also performs as the Muscle Space can be treated as a vector of a scalar that you can linearly interpolate as opposed to quaternions or Euler angles. Another beautiful thing is how well Muscle Space interpolates. It can be directly applied to any Humanoid Rig and it always create a believable pose. One beautiful thing about Muscle Space, is that it is completely abstracted from its original or any skeleton rig. In the end, the Muscle Space is composed of at most 47 Muscle values that completely describe a Humanoid body pose.
A range of zero (min= max) for a bone axis means that there is no Muscle for it.įor example, the Elbow does not have a muscle for its Y axis, as it only stretches in and out (Z-Axis) and roll in and out (X-Axis). The Muscle Space is the set of all Muscle normalized values for the Humanoid Rig. A specific Humanoid Rig can augment or reduce the range of a Muscle Referential to augment or reduce its motion span. The range is not a hard limit, instead it defines the normal motion span for a Muscle. Note that the Muscle normalized value can go below or over to overshoot the range. A Muscle Referential is essentially a pre and post rotation with a range and a sign for each axis.Ī Muscle is a normalized value that moves a bone for one axis between range. It identifies a set of human bones and creates a Muscle Referential for each of those. The Humanoid Rig is a description on top of a skeleton node hierarchy. Mecanim Humanoid Rig and Muscle Space are an alternative solution to the standard skeleton node hierarchies and geometric transforms to represent humanoid body and animations. Please refer to Unity Documentation for general setup and instructions.
#Esoteric software spine one skeleton multiple poses how to
How it works, strengths and limitations, why some choices were made and hopefully some hints on how to get the best out of it. This post explains the technology behind Mecanim Humanoids.