Summary
While testing the Substrate system in Unreal Engine 5.6, enabling Translucency still preserved the Anisotropic shading features correctly.
However, in Unreal Engine 5.7 and 5.8, enabling translucency causes Anisotropy to stop working entirely.
What Type of Bug are you experiencing?
Rendering (Graphics / Niagara)
Steps to Reproduce
- use a substrate slab BSDF node.
2.set Albedo and F0 to 1, Roughness to 0.3, Anisotropy to 0.8, now a anisotropy effect on preview model.
3.set blend mode to translucent and set lighting mode to surface forwardshading
4.the anisotropic effect is missing.
Expected Result
Translucent Substrate materials should retain anisotropic shading behavior
Observed Result
The material loses all anisotropic highlights and behaves as if anisotropy is turned off.
Affects Versions
5.8
Platform(s)
Windows
Additional Notes
I checked the shader source code and found a behavioral change inside SubstrateEvaluations.ush. Compared to 5.6, bHasAnisotropy was added an additional requirement SUPPORTS_ANISOTROPIC_MATERIAL. After remove this requirement, I can see the Anisotropic Effect after Enable translucency