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Splootches in Ray-Tracing

Hi, I’ve stumbled across white splotches in real-time raytracing. The first picture is a High-Resolution Screenshot, the second is a Level Sequence Rendering. I’m suspecting the Sky Light. What’s interesting it happens in every scene. I do relatively the same setup but in some scenes I see them and in some don’t.

Yeah, it’s probably the skylight. I get the same. One thing I did was modify the DFAO for a smaller Radius, which reduces it, but may not remove it entirely. Another potential way to fix it, in addition to other techniques, is increase Shadow Resolution in the directional light. There’s more in the skylight, and via cvars, that can solve it. I need to scour a project to remember what it all was for dynamic, ray-traced lighting.

I think it’s related to any denoiser. Probably the skylight one. Try to disable the denoiser of sky from console command. If there is a difference, you will have spoted the guilty one. (And maybe it will look even better, if you use enough samples).

Thank you, I’ll test it on Monday. The scene is pretty simple, everything is set by the default, apart from the light intensity of course.

I’ve found that the issue coming from the Anti-aliasing and High Resolution features in movie render. I’ll play a bit with settings further. But those are two features which give those splotches. Anti-aliasing with TemporalAA gives a clean picture whereas all other options doesn’t

So, what I’ve found so far. Smaller DFAO was great advice. What’s interesting is that before I used Skylight in Static mode, what wasn’t looking right for raytracing but gave the best result. With a smaller radius, it started to work in Stationary mode as well with a practically similar result.

That’s what I found in using smaller DFAO for dynamic lighting, even in stationary mode. It probably is associated with how DFAO and distance fields are calculated differently for movable lights. Another potential help is changing AO in the post process volume to be in World Space Units, then reducing or adjusting the intensity and a few other settings for it. Bias and Power were two that I noticed had a significant impact to the look of AO shading, though they’re probably not going to resolve everything. A number of cvars of AO could be functional too, so simply bring up the console via tilde (~) or activate the Output Log from Window > Developer Tools (displays in Content Browser), and type “r.ambientocclusion.” for a list. Typing “r.shadow.” is another list, and “r.raytracing.”.