Bug: Attribute Create SOP renders black polygons with Geometries with normal mapping

When I apply an Attribute Create SOP to Calculate Tangents and feed that SOP to a Geometry that uses a Material that uses Normal Mapping, some or all of the faces go pitch black in the render.


I can understand this happening with weird imported models, but it happens even with fully native stuff like the Wireframe SOP.

Attached is an example:

attrib_bug.toe (4.3 KB)

Things I tried that didn’t help:

  • inverting normals
  • changing the pixel format of the normal map top

Win 10, 2021.15800

Related topic: Checking Compute Tangents in Create Attribute makes the render of the SOP suddenly go pitch black

Similar issues on other forums: Normal Map gives black render on half the surfaces - Blender Stack Exchange
and cycles render engine - My Normal Map makes my material black - Blender Stack Exchange
and Normal map, sections go black?? - #9 by coonerboy - Materials and Textures - Blender Artists Community
and Applying Normal Map Make Everything Appear Black? - Modelling - Core 4D Community
and https://forum.unity.com/threads/model-and-sky-turns-black-after-adding-a-normal-map.822486/

Recurring theme is NaN values (dunno what that means), poorly calculated tangents, inverted normals.

Hey @matijaerceg

Thanks for the report and sample file.

I’ve logged an issue for a developer to look into it.


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