Finding the real world position of a vertex that is driven by a joint

[JonVarner]

Hey all, I am currently working on a project that has a mesh driven by joints. However, during the animation I need to be able to determine the actual real world position for one of the vertices. I have tried

.getVerticesData(BABYLON.VertexBuffer.PositionKind, true)

This gives me the position of the vertex(s)  at its starting point and not where it actually is as it deforms. I also tried

BABYLON.Vector3.TransformCoordinates(vertex, mesh.getWorldMatrix()

This of course gave me the real world coordinates of the vertex at its starting point. Again not quite what I was after.

So I guess I am hoping that someone can point me in the direction of finding the location of a vertex after it has been moved by a joint. Thanks.

 

[Guest]

Hello! unfortunately (in your case) the bones are processed on GPU side to be fast!

So you cannot get the real world value of a vertex directly unless you turn off the GPU processing. It is possible but it will consume more CPU.

You can do it with mesh.computeBonesUsingShaders = false. In this case all the transformed values will be in  getVerticesData(BABYLON.VertexBuffer.PositionKind, true)

 

[adam]

If you don't need the exact vertex position, you might be able to use bone.getAbsolutePositionFromLocal.

https://github.com/BabylonJS/Babylon.js/blob/master/src/Bones/babylon.bone.ts#L1045

[adam]

Here's an example:

https://www.babylonjs-playground.com/#EG1J26#1