How to fix backface culling when importing GLB?

Questions
1

Hi guys,

Some meshes show backface in my imported model

[GLB] Backface culling issue when cloning mesh | Babylon.js Playground (babylonjs.com)

I tried to copy overrideMaterialSideOrientation from the original mesh but it didn’t help. I believe I shouldn’t disable backface culling just to bypass this issue.

Any suggestion?

Thanks

2

Can you explain what part of the scene is wrong? If loading the GLB is showing faces that you are not expecting, the GLB is probably wrong. I don’t see any materials in your GLB that is marked as doubleSided.

3

Sorry for the late response, I had some updates in the playground link

[GLB] Backface culling issue when cloning mesh | Babylon.js Playground (babylonjs.com)

The second pipe shows backface after cloned

image

This is a result when I disabled backface culling

image

4

The problem is that the original mesh is an instanced mesh. An instance mesh doesn’t use its overrideMaterialSideOrientation so the real one comes from sourceMesh. We should perhaps forward this to the source mesh automatically. @sebavan @Evgeni_Popov Any thoughts?

Here is the fixed PG: https://playground.babylonjs.com/#RH1RMV#2

@thinh.pham Why are you cloning the instanced mesh? If you don’t want the loader to create instanced meshes, you can tell it not to by setting the createInstances property to false: https://playground.babylonjs.com/#RH1RMV#3

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5

Indeed, createInstances property should be the right choice. Thanks for the suggestion.

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6

The new mesh is created from scratch in the PG, so I don’t see any other solution than manually copying the value of overrideMaterialSideOrientation (the name clonedMesh is a bit misleading, the mesh is not created by calling clone).

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7

What I mean is whether InstancedMesh should override its overrideMaterialSideOrientation property like what we do for many other properties (e.g., visibility or skeleton, etc., etc.) so that it gets the value from the sourceMesh. This property is a bit different in the sense that it is only available for Mesh and not AbstractMesh so maybe it’s not quite the same.

8

For instances, overrideMaterialSideOrientation is already the one from the source mesh, as they are rendered with the same material than their source mesh:

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