Hey, team. I have come across something strange with one of my files. When using Cycles, point lights shine more up than they do down. I know that sounds weird, so look at the difference in the same file between Eevee:
I’m using Blender 4.3.2 on an Apple Silicon Macbook Pro. I tried in a new blank scene, and the lights behaved correctly (they had the same influence in the positive and negative Z axis). Any ideas on what I can try to change?
Maybe it’s the material? This could happen if a normal map was wrong or the material’s normals were manipulated in some way. Does the problem persist if you use a different material?
Great suggestion, @etn249! I still don’t have the exact reasoning behind the issue, but it does appear to be related to the object’s normals! Check it out.
I removed the world shader, I hid all other geometry, I changed the object’s shader to be a simple diffuse color, and I toggled between shade smooth and shade flat:
…so, my guess as to what it is - the side faces of my geometry were shaded smooth, and the bottom faces were shaded flat. Because the normals are being interpolated between smooth and flat at a right angle - maybe it did some weird normal twisting. I just added another edge loop to my geometry so that the normals where the light as is not interpolating across smooth and flat shaded faces:
That being said, I’m not sure why it renders correctly with Eevee, but incorrectly in Cycles…A mystery…
