It’s 2021 and I’m not sure if I am writing this topic too late but recently I’ve been playing around with Distance Field Ambient Occlusion and found some little settings to tweak which make the results “significantly” improved. I thought I’d better share this for the guys who are trying to use DFAO after this moment. DFAO is performance friendly and used in Fortnight so you might also want to use it in your project.
First of all, DFAO is for open type levels and fully dynamic levels to achieve darker interiors and shaded areas. NEVER use DFAO for arch viz as it’s quality is not reliable enough to achieve realism.
I’m only going to talk about DFAO and not going to talk about Distance Field Shadows. I’ve lit the scene with only skylight with DFAO enabled without directional light and SSAO so that u can easily see how it works.
Once you apply DFAO into your level you’ll notice that it has a lot of artifacts, the shadows are very harsh and pretty much unusable.
To disable these pitch black artifacts, turn on two sided Distance Field Generation in Mesh Details panel of your meshes. I’m not sure what kind of cons it will bring but this thing magically solves pitch black artifact issue in my scenes. You might wanna set DF resolution scale to more than 1 if the mesh in your scene is large or complex.
Now tweak these settings in SkyLight to make the shadows less harsh and evenly distributed.
- Brings up Occlusion Max Distance if you want large shaded areas. You can bring it up pass 1500.
- Occlusion Contrast to 0.5 to make the shadows more defined.
- Min Occlusion to 0.2 to lighten very dark harsh black shadows. This make overall DFAO shadows lighter.
- Occlusion Exponent value to more than 1 to make the shadows darker again.
- Occlusion Combine Mode to “Multiply” if you want to combine DFAO with other AOs like SSAO.
You might also wanna play with Lower Hemisphere Color to achieve dark ceilings.
Now look at the final results!
The shadows are well distributed, the areas are well shaded, no pitch black problem and it just looks better. I hope this topic will help your projects.
EDIT: If you want further optimization, only generate DF for walls and roofs, disable DF for probs by setting DF resolution to 0 and use SSAO for a nice AO around the probs.