Developer Notes

This issue has been closed as 'Won't Fix' due to an extended period of time without updates. If this issue is important to you please let us know by posting on the AnswerHub or UDN, and Epic will re-open the ticket for further review.


When using a Two-Sided Material and Shadowing Two-Sided for a Plane or Landscape, with non-flat normals, there are parts of the material which are still illuminated.

I have provided a test project so you can simply rotate the light source, rebuild the lighting, and see this issue in effect.

Steps to Reproduce

1. Download and open
2. Open project and rotate the light source so it is coming from below the actors placed in the world.

Expected The top of the plane/landscape is completely dark

Outcome Parts of the surface are illuminated and visible

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Won't Fix
Affects Versions4.
CreatedDec 17, 2015
ResolvedJan 25, 2017
UpdatedApr 27, 2018