AntonSynytsia wrote:Conducting a few tests, I found that skeleton containers now work properly if the root body is static, which is very desired! They don't work, however, if any of the linked bodies are static. It's not much of an issue though. I do think, however, that skeleton containers should consider infinite-massed bones. Imagine having a bridge linked with hinge joints with the first and the last body static. That is one case where static bones are necessary.
Ah now we are talking, yes one of the rule for the skeleton is that that only the root bone can be static, however this is not a problem because that's the improvement of 3.14
you can attach any of the link to any external body that is not part of another skeleton, or you can link any tow body part of the same skeleton using the cycling joint
below is a sketch of a skeleton using cycling joint to link internals and external bodies.
- skeleton.png (16.56 KiB) Viewed 3762 times
I also found that changing the stiffness as described in my first post makes skeleton containers stronger, though also unstable in certain ways. So, I think the stiffness should be left as it is. Removing the clamping and modification wouldn't yield desired results if implementing skeleton containers.
yes that a really bad thing to do, it has to do with a theorem of linear algebra that say that a positive definite matrix must have positive Eigen values. making the stiffness value less that one scale the diagonal of the mass matrix, and that can make the matrix not PSD. That's a really bad thing to do.
I would really like to understand the reason skeleton container can't support looped bones.
One question though, what are cycling joints and when is it necessary to use the
the reason is that for some king of graph, the matrix representation lead to algorithm that can be fasters that the general way of solving them. A skeleton is a special king of graph that can called acyclic, this mean that each nor can only have one parent. put another way a graph is acyclic if the forest visit each node and each only once. this kind of graph can be factored in linear time.
That is what the Newton Skelton is.
as you can see the topology of the graph forbid connecting any two of the node because down that break the acclivity rule. but that's where NewtonSkeletonContainerAttachCyclingJoint come in.
you can now connect any two nodes or any now to any external body using the cycling function.