Maya to FBX to Unity vertex count inconsistency

Unity Engine
1

Hi,

I’m trying to use the morph animation scripts, so I took a model of mine in maya and exported 3 different blend shapes to different FBX files.

I imported them into unity and they had slightly different vertex counts, so I could not use the script with them. I tried changing the normal/tangent generation/import settings to all of the combinations, but still could not align them.

Is there any way I can control this process to make sure that they get the same amount of vertices?

Note : when I opened the exported FBX files in maya they had the same vertex counts.

2

vertex count difference can be the result of difference of :

  • Uvs,
  • soft and hard edge on each model,
  • material (am anot sure about it… but it affect the batch count… hmm…)

After that I do not see where could be the problem.

Do you have the FBX files we can try it out?

Try a MP if you want I will check that tomorrow morning.

3

I tried some more (updating maya’s FBX exporter plugin etc) and still got nothing.

I attached my model after I did the following :

  1. Open maya
  2. Edit blend shapes to the pose I like
  3. Duplicate model
  4. Delete original
  5. Export duplicated model

I did this twice for two poses, and those are the present FBX files. When I import them in unity, I get slightly different vertex counts (check out the fac and InnerMouth submeshes).

I tried two things to test whether the FBX actually has different poly counts :

  1. Import the FBX into the new scene. Got the same vertex counts for both.
  2. Use Autodesk’s FBX converter to save the file in DXF format and open it with OpenSceneGraph’s viewer. Same vertex count for both.

Does anyone have any ideas?
Thanks!

389508–13401–$diffpolycounts_195.zip (904 KB)

4

Alright…

The bug is on the Head and InnerMouth mesh.

On InnerMouth Uvs are destroyed.
Uvs car affect the Vertex count in Unity.
If you apply an Automatic mapping on both InnerMouth on the FBX files you attaches to this thread, delete your history and import the full model again. vertex count issue will be fixed for this mesh.

Now for the Head :
I didn’t success to fix the vertex count issue but…
If you apply the following command to the head :

  • polyMergeVertex -d 0.000000001;

… you will see an optimisation of 2 vertex.
this means 2 vertex share the same coordinate and this is not very good… this could maybe affect your Uvs.
I am not sure but…

and same with the innermouth, if some vertex arrent mapped, this could create one more issue on the vertex count…

Try this :

  • Take you main model
  • Apply the following command : polyMergeVertex -d 0.0000001;
  • Delete all history and apply an automatic mapping on each parts.
  • once you cleaned history one more time… you can try to deform the face for one more test on copy.
  • and then export the 2 version of the model.
5

I solved this issue changing the FBX importer parameter Normals to None (Apply) and then back to Import (Applay again)…if you do this you can see the vertex count of your model changing in the preview window (don’t forget to load the meshes again in the MeshMorpher script, it does’n update them automatically).

regards.

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