When I set a material to URP Unlit and set the render face to back it will only render the front face. Is this a bug or is their a work around? (Tested on a standard unity sphere)
In the end I want to be able to create an unlit shader that uses the poly spatial lighting node that renders to both faces.
It’s a known issue; the root cause is that RealityKit’s UnlitMaterial (and ShaderGraphMaterial) lacks an option to control the cull face, so it always renders front faces (only). We’ve asked Apple for the ability to control the cull face in those material types; feel free to do so as well via their Feedback Assistant. Currently, the only material type that supports is is their PhysicallyBasedMaterial (so, our URP/Lit or Standard shaders).
We’re looking into the possibility of generating additional geometry automatically to work around this, but until we do, your best option is probably to do it yourself: that is, if you want to an unlit/shader graph material that’s two-sided, you’ll have to add another set of triangleIndices with the opposite winding order to your mesh.
I made a shader graph based Lit Shader Graph, but it still couldn’t render the back only. Do you mean that only the urp default Lit material can render only the back
Correct, yes; only the non-shader-graph “Universal Render Pipeline/Lit” shader (and the equivalent for the built-in render pipeline, “Standard”) will respect the Render Face setting, because (prior to visionOS 2.0 beta) only the RealityKit PhysicallyBasedMaterial had an option to set the cull face. That’s been remedied in visionOS 2.0 beta (cull face options added to UnlitMaterial and ShaderGraphMaterial), so our next 2.X release (which will require the visionOS 2.0 beta and Unity 6) will support the Render Face option for URP/Unlit and shader graphs.