These skinning transformations seem a lot different from the rigid transformations described later in the slides. For one, each point on the model is transformed differently depending on how close it is to different parts of the skeleton, which I assume can be done with some weighting system.
However, such transformations of the surface can compress or expand the volume of the model in general, which would look unnatural. I'd love to know more about some of the details of how skinning works. It seems like there should be multiple ways to do this heuristically with different performance tradeoffs.
nphirning
What software is this?
sarukkai
The skinning transformations are in fact implemented with weightings corresponding to each vertex for each bone in the skeleton. In the models I have seen, weightings are generally assigned manually by the artist skinning the model, with the artists choosing whatever weightings look most natural. However, there are definitely "smart" default weights that we can assign to vertices through considering the distances to the nearest bones, or "bone heat," for instance weighting the relative influence of different bones with quadratic falloff based on the distance from those bones. These are good starting points which can then be manually customized.
InfinityAxiom
Rigging is hard, and is a major reason why animators exist and get paid. Mixamo is a cool company (founded out of Stanford!) that offers auto rigging service through their pipeline. It is interesting to check out their website where you can view hundreds of rigged models doing different animation, and is also an excellent source to find assets for a game: https://www.mixamo.com/#/
These skinning transformations seem a lot different from the rigid transformations described later in the slides. For one, each point on the model is transformed differently depending on how close it is to different parts of the skeleton, which I assume can be done with some weighting system.
However, such transformations of the surface can compress or expand the volume of the model in general, which would look unnatural. I'd love to know more about some of the details of how skinning works. It seems like there should be multiple ways to do this heuristically with different performance tradeoffs.
What software is this?
The skinning transformations are in fact implemented with weightings corresponding to each vertex for each bone in the skeleton. In the models I have seen, weightings are generally assigned manually by the artist skinning the model, with the artists choosing whatever weightings look most natural. However, there are definitely "smart" default weights that we can assign to vertices through considering the distances to the nearest bones, or "bone heat," for instance weighting the relative influence of different bones with quadratic falloff based on the distance from those bones. These are good starting points which can then be manually customized.
Rigging is hard, and is a major reason why animators exist and get paid. Mixamo is a cool company (founded out of Stanford!) that offers auto rigging service through their pipeline. It is interesting to check out their website where you can view hundreds of rigged models doing different animation, and is also an excellent source to find assets for a game: https://www.mixamo.com/#/