GetBlendShapeFrameVertices() Doesn't work for imported blend shapes !

Hello,

We are working on a character customization system and we need to merge several SkinnedMeshRenderers into one.

Everything is working fine except, we need to copy blend shapes from the head mesh part to our combined mesh and it's just not working.

There is a method called: GetBlendShapeFrameVertices() that returns a weight and vertex positions, normals, tangents deltas for specified blend shape frame but when I call it on my head mesh with specified blend shape index and frame index - it just returns all zero vectors ...

Code (CSharp):

1.  
2. int shapeID = meshToMerge.GetBlendShapeIndex("all_vertex_move"); // test blend shape - works in editor
3. int framesCount = meshToMerge.GetBlendShapeFrameCount(shapeID); // returns "1"
4. float frameWeight = meshToMerge.GetBlendShapeFrameWeight(shapeID,0); // returns 100f
5.  
6. Vector3[] deltaVertices = new Vector3[meshToMerge.vertexCount];
7. meshToMerge.GetBlendShapeFrameVertices(shapeID,0,deltaVertices, null, null);
8. for(int a=0; a<meshToMerge.vertexCount; a++)
9. {
10.      Debug.Log("delta vertex no. "+a+" = "+deltaVertices[a].ToString()); // returns (0.0, 0.0, 0.0) for every element
11. }
12.  

Interestingly - this test blend shape ( "all_vertex_move" ) is visible in the editor and works fine on our head mesh.

On the other hand when I manually create a new blend shape for my head mesh ( just for test purposes ) - I can successfully retrieve all deltas I specified in the AddBlendShapeFrame() call:

Code (CSharp):

1.  
2. Vector3[] randomDeltas = new Vector3[meshToMerge.vertexCount];
3. for(int y=0; y<newMeshVertexCount; y++)
4.      randomVertices[y] = new Vector3(UnityEngine.Random.Range(-10,10), UnityEngine.Random.Range(-10,10), UnityEngine.Random.Range(-10,10));
5. meshToMerge.AddBlendShapeFrame("random_shape", 100f, randomDeltas, null, null);
6.  

For such added blend shape I can use GetBlendShapeFrameVertices() and get all proper deltas.

Please help. I'm out of ideas :/

Cheers,
Stan

 

can you check if you shapeID is different than -1
If I remember well the name in the editor and internally is not necessary the same one

 

shapeID is 20 in this case ( it is due to all previous shapes ). I can retrieve it's frame count and frame 0 weight - "only" deltas are all zero

 

It look like a bug then.
Please log a bug and we will investigate

 

Oh i see

Is there any workaround for this in Your opinion ? We just need to copy blend shape data in any way

 

It should work, but for an unknow reason it doesn't seem to be working.

I don't think there is another way

 

In my project I am facing the same problem. I managed to solve this issue by using SkinnedMeshRender's BakeMesh method.First clear all BlendShape weights, Then bake each blend shape by setting its weight to 100. Just like this
for(int bi = 0; bi < blendShapeCount;bi++)
{
clearAllBlendShapeWeight ();
string shapename = skinnedMesh.GetBlendShapeName (bi);
int shapeid = skinnedMesh.GetBlendShapeIndex (shapename);
skinnedMeshRenderer.SetBlendShapeWeight (shapeid, 100.0f);

//Vector3[] diffvertices = new Vector3[skinnedMesh.vertexCount];

Mesh tmpmesh = new Mesh ();
skinnedMeshRenderer.BakeMesh (tmpmesh);//From tmp mesh you can get everything you want
}

 

I just encountered the problem you mention, and what you say is partly false for me.

It seems that deltaVertices[a].ToString() indeed does returns (0,0,0), but the bug is with .ToString(). If I Debug.Log(vert.magnitude) or Debug.Log(vert.x), the data is actually there.

So everything works as it should, it just looks like .ToString() doesn't return the data correctly with Vector3s?

Can anyone confirm this is how it is on their side as well?

 

I think you are right, I encountered the same situation, it should be the problem of Vector3 precision.