Check BlandShape Normal

2020-11-16 11:21:12 +0900 +0900
Last modified November 17, 2020: Add blendshape normal validation page (de8e1d1)

Since Unity 2018, when importing fbx into Unity, the BlendShape normal is automatically recalculated. As a result, there is a possibility that artifacts are produced on the model’s surface.

Validate surface normal using MToon’s debugging options

Drag fbx to the Hierarchy window and select it. In the Inspector, click Select -> Materials -> Extract Materials and choose a folder to save these materials. Next, select all materials and change Shader to VRM/MToon.

To visualize the surface normal, go to Options - Debugging Options - Visualize and select Normal:

debug normal

Select a GameObject containing SkinnedMeshRenderer with BlendShape. Drag the slider while observing surface normals:

debug normal

We can see surface normals around nose tip and mouth are not correct.

Fix BlendShape normal

To fix BlendShape normal, in the fbx’s inspector, click Select -> Model -> Legacy Blend Shape Normals and check the box.

Now confirm whether the BlendShape normal has been fixed:

fixed normal

VRM - humanoid 3d avatar format for VR