Terrains 512x512 and up + Terrain Shadows = Unusable Framerate in Editor

[beo6]

When enabling Terrain Shadows and using a Terrain that is 512x512 or up, the Framerate in the Editor 3D View becomes unusable and GPU usage goes up to 100% and coolers ramp up audible. Even 256x256 goes up to 90% GPU utilization and low framerate.

I have a RTX 3090 with newest drivers.

[beo6]

Looks like its an issue if both Tesselation and Terrain shadows is enabled.

It doesn't matter if Tesselation is set to Low or Ultra. Framerate only returns to good if Tesselation AND/OR Terrain shadows is disabled.

Also doesn't matter if i use Material on the terrain with tesselation or not.

[Josh]

Yeah, can confirm, terrain with tessellation is fine, but when you enable terrain shadows it slows down massively.

Terrain shadows without tessellation is fine.

I suspect the subdivision calculation for othrographic projections is wrong...

[Josh]

Easy fix: I disabled tessellation on shadow rendering. Maybe I will revisit this in the future.