Hi there, I would like some help to know if i’m not doing something really wrong.
I cannot find a place on the internet that discuss this behavior of LTC (linearly transformed cosine) which is what Unreal (4.20), Unity (HDRP) and Eevee uses for area lights:
Notice the abnormal reflection at the bottom of the sphere and the Suzanne.
I don’t have the unreal engine installed to do the test myself so it would be nice if someone kindly do the experiment and post the result of a similar setup in Unreal or Unity (HDRP).
The setup is just a rather tiny area light (see screenshot) without shadows, and an object with a material 100% metallic and 2% rough.
In blender increasing roughness makes the artifact vanish progressively. Making the area light bigger also fade the artifact.
If anyone can confirm or infirm that the bug also appear in Unreal / Unity that would be nice.