Bug with Alembic and SubD

[Rikk The Gaijin]

I found a weird problem when trying to subdivide an alembic file with a sss material.

The image above is the scene without any subdivision.
The image below is with one level of subdivision. As you can see the shader changes completely and the material becomes gray!

It happens only with alembic. I tried the same scene as OBJ and the subdivision worked fine with no side effects on the material.
Any idea?

[Rikk The Gaijin]

No replies?!
I can send the scene if needed!

[Rikk The Gaijin]

[roeland]

Can you post a render of the interpolated shading normals output of the info channels kernel, without and with subdivision?

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Roeland

[Rikk The Gaijin]

Can you post a render of the interpolated shading normals output of the info channels kernel, without and with subdivision?

Super-Roeland as usual knows his stuff...
The render of the normal does indeed get fucked up with the subdiv ON.

[roeland]

The normals are flipped when subD is enabled, but I can't reproduce this issue here. What are the other settings under the common import preferences?

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Roeland

[Rikk The Gaijin]

The normals are flipped when subD is enabled, but I can't reproduce this issue here. What are the other settings under the common import preferences?

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Roeland

Those are default settings, I haven't touch them. At this point it's easier if you try the scene yourself, I send you a PM

[roeland]

OK thanks, I will have a look.

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Roeland

[roeland]

The mask is exported using clockwise winding order, so in the geometry import preferences for the alembic file you need to enable "flip face normals".

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Roeland

[Rikk The Gaijin]

The mask is exported using clockwise winding order, so in the geometry import preferences for the alembic file you need to enable "flip face normals".

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Roeland

Thank you Roeland, but why does it happens? Is it a bug in the Maya Alembic exporter? It doesn't happen with OBJ.