Help wanted with a dynamic skeleton

[mihai-ene-public]

I'm attempting to build a skeleton based on some rig data written in a json file.
For a bone, in this json we have the bone name, it's parent, head and tail info from which bone head and tail positions can be calculated.
Head and tail infos for bones refer to some vertex indices in the mesh.
The corresponding mesh is dynamic, so the skeleton should be also updated.
I was able to build the node parenting.
It seems I'm unable to calculate the skeleton node transform.
For example I have some questions:

• the node.Transform.Position should be relative to its parent tail position, or should be it's head position in mesh coordinates?
• how would one calculate the scale and rotation.

Here is the code I have so far:

var skeleton = new Skeleton() { Nodes = rig.Skeleton.Nodes.ToArray() };

 Vector3 boneHeadPos = GetBoneEndPosition(rigBone.Head);
 Vector3 boneTailPos = GetBoneEndPosition(rigBone.Tail);

 var boneNodeIndex = Array.FindIndex(skeleton.Nodes, n => n.Name == rigBone.Name);

ref var boneNode = ref skeleton.Nodes[boneNodeIndex];
var boneDirection = boneTailPos - boneHeadPos;
var boneLength = boneDirection.Length();
if (boneDirection.LengthSquared() > 0.0f)
{
      boneDirection.Normalize();
}
var boneRotation = Quaternion.LookRotation(-boneDirection, Vector3.UnitY) * Quaternion.RotationAxis(boneDirection, -rigBone.Roll);

boneNode.Transform = new TransformTRS
{
    Position = boneHeadPos,
    Rotation = boneRotation,
    Scale = Vector3.One
};

[Doprez]

I guess what you could do to know for sure is import a test mesh with a built skeleton and see what the values are when impored into Stride. I think its meant to be relative to the parent node but I havent built a skeleton from scratch before in Stride.