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