Impact of Mesh Topology on the Refraction Behavior of Glass in Unreal Engine 5 (Especially Curved Surfaces)

Impact of Mesh Topology on the Refraction Behavior of Glass in Unreal Engine 5 (Especially Curved Surfaces)

Hello Unreal Engine 5 pros,

I have a question regarding the impact of mesh topology on the realistic refraction of glass in UE5. As a professional 3D modeler, I primarily use CAD-based software like Rhino, which doesn’t require extensive adjustments to topology and edge flow, unlike 3ds Max or Blender.

In traditional render engines like Corona or V-Ray, achieving accurate light behavior and refraction in glass materials necessitates using quad meshes, especially on curved surfaces. Adding weighted normals or playing with smoothing groups often doesn’t resolve shading issues, resulting in jagged and inaccurate refractions (see attached images: Pic 1 with quad mesh, showing perfect refraction, vs. Pic 2 exported from Rhino without quads, showing jagged refraction).

When exporting models from Rhino as meshes in FBX or OBJ formats, the resulting meshes are precise but not in quad form. This non-quad topology causes issues with physically accurate refraction in traditional render engines. These refraction shading issues are particularly noticeable on curved surfaces!

My question is: Does Unreal Engine 5 offer specific modifiers or light simulation algorithms that can effectively tackle these shading issues on curved glass surfaces in a clear and realistic manner? (As I mentioned, solutions like the Weight Normal modifier in 3ds Max aren’t satisfactory, and I have extensive experience with such methods.) If UE5 provides solutions for these challenges, I would strongly consider shifting my focus to UE5 over traditional render engines reliant on mesh topology and normals.




The experimental Substrate material pipeline might help here?

ref - Overview Of Substrate Materials In Unreal Engine | Unreal Engine 5.4 Documentation | Epic Developer Community

It’s a new rendering paradigm for materials in that it more-accurately reflects (lol) the bi-directional scattering of light. That light just doesn’t reflect off-of and get absorbed-by a material but that the light can then pass to a NEW material, with different properties and be properly, well, shown.

Unsure it would help here but it’s not-the-same as what we are using today with the PBR pipeline, and it SHOULD offer some improvements with regards to refraction, non-opaque materials.

Just a thought. Otherwise to my limited knowledge I am unaware of any glass-specific type controls you are looking for. You could write your own in the materials-shader if you know better, but OOB I don’t think the engine does what you are asking.