Pick bone only Is it possible?

Questions
1

Hello,

Is it possible to choose a bone only? For example, I have a character with a skeleton and I wish for example by clicking on the head to select the bone of the head and not the mesh to make a rotation on the bone select.

Or I wish I could get the index of the bone by clicking on the head for example.

How can we do that?

2

Hey!

once you have the picked mesh, and the picked face you can probably get (not easy but I can help) the matricesIndices values that are the IDs of the bones that influence the current mesh

3

Ok, I’ll try to follow this track in a PG to see how I can get that.

But I can not find the matricesIndices values ​​so far. And I’m not sure of my method for selecting a face.

https://www.babylonjs-playground.com/#BCU1XR#725

Thanks for the help

4

So yes this is correct and now instead of getNormal you need to come with something like getTExtureCoordinates but with the VertexBuffer.MatricesIndices instead:

5

I use now this:

var matricesIndices = pickResult.pickedMesh.getVerticesData(BABYLON.VertexBuffer.matricesIndices);

But it return “Null”. Did I do something wrong?

https://www.babylonjs-playground.com/#BCU1XR#731

I think I do not even understand what I’m doing. :upside_down_face:

6

This will work better:

var matricesIndices = pickResult.pickedMesh.getVerticesData(BABYLON.VertexBuffer.MatricesIndicesKind);
7

What a small typo can do to your confidence :slight_smile:

Seems like you know exactly what you are doing, as always

8

Thank you Deltakosh, I get data in a large table. But whatever the location of the mesh where I click, it’s the same table of data.

What should I do now to retrieve the index of the selected face bone.

https://www.babylonjs-playground.com/#BCU1XR#733

Hi @RaananW ,

Down I happen to do things without really understanding what I’m doing. I do it because I imagine it must be like that, but without understanding what I write, why.
Here for example, I recover the MatricesIndices but I do not know what I have to do and I do not know what are matrices concretely. :confused:

9

Once you get the matrices indices data, you need to do like in the code I linked, you need to

So let say we have something like:

let vertexId = indices[this.faceId * 3];
let bone0 = matricesIndices[vertexId * 4];
let bone1 = matricesIndices[vertexId * 4 + 1];
let bone2 = matricesIndices[vertexId * 4 + 2];
let bone3 = matricesIndices[vertexId * 4 + 3];
1 Like
10

Ok, so if I understand correctly, bone0 corresponds to the index of the selected bone.

I have difficulties to understand. Sometimes the return data is 2, 3, 0, 0, or 5, 0, 2, 0 or 64, 0, 0, 0

https://www.babylonjs-playground.com/#BCU1XR#734

11

yes the data is correct (0 means no bone)

12

So, bone0 is the bone I need? How to know if it is the index of the bone of the head for example when I get a value bone0 and bone2.

I see that bone0 always has a value, I guess it’s the index I’m looking for. So I can ignore others. Is it correct ?

Thank you Deltakosh

13

If you are sure that only one bone is used to influence a vertex then yes, bone0 is enough

then you should be able to do something like skeletons.bones[bone0] to get your bone object

14

Ok, that’s perfect then. Thank you very much for your help.

1 Like
15

Always :wink:

16

Final code encapsulate in a function.

Could not this be added to the engine in the file pickingInfo.ts ? I can do the PR if needed

https://www.babylonjs-playground.com/#BCU1XR#735

17

It is a bit complicate as people may want to get all the bones and not the first one. There is also the case where we have 8 and not 4 bones (and in this case the MatricesIndicesExtraKind is used)