Download

Big black artifacts with DF shadows

I posted this on the Answerhub a few weeks ago, but got no response. If anyone here has advice, I’d appreciate it.

I love the soft shadowing effect of DF shadows for my dynamic lights, but I’m having a ton of trouble getting rid of artifacts.

In my lighting test map, I have a small house that I’ve imported several ways - as a single mesh, as several meshes (broken down by room), as modular pieces. I’ve been playing with the lighting to see how I can get the best result, mostly dealing with light leaks through walls and DF artifacts.

Importing the entire house as a single mesh, the DF meshes are a mess, even with increased resolution, missing entire pieces of geometry. This is improved by splitting the mesh up into smaller pieces, but then I get nasty black artifacts at certain points where two or more meshes are close together.

Reference images are attached showing a corner that exemplifies the problem. In order:

  1. The corner. Interior wall and exterior wall are separate static meshes. The wall is 20cm thick. The point light is using DF shadowing. Mesh DF resolutions are increased until there’s no visible result from increasing them further.
  2. The same view with DF meshes visualized.
  3. And again with DFAO visualized.
  4. And the exterior mesh (directly on the other side of the wall). The point light is casting DF shadows. There are no artifacts on this side.

I’m also seeing similar black artifacts elsewhere where separate meshes are near each other (like where the roof meets the exterior sides or exterior sides meet each other).

How can I get rid of these artifacts? Is it an issue with the meshes, the way they’re aligned/spaced, or is it a fundamental issue with DF shadows that I can’t avoid (and should therefore just go with regular shadow maps)? Increasing DF offset helps slightly (but still doesn’t produce an acceptable result), but creates leaks.

Thanks in advance for the help!

Edit: I forgot to mention - this only occurs with movable lights. There is no such dark spot using a stationary light, once lighting is built (it is there pre-light build in the preview shadow - I assume this is because it’s using shadowmaps, not DF shadows). But there will be places I need to use movable lights, so this is still something I’d like to fix.

This issue is coming from your distance field mesh. It casts shadow on your static mesh, wich looks like artifact. Split your mesh into modular pieces to get accurate distance field representations.