RTX GI Shadows Disappear With Camera Distance

Development Rendering
1

Hello,

I am using a RTX raytraced environment.

I’ve set-up a simple test scene with Ray Traced GI set to Brute Force - 16 bounces, 64 Samples Per Pixel

The spheres are lit by bounced rect light on the right plane.

I noticed that objects that are further away from the camera get their shadows “thinner” or even disappearing all together. (see attached)

This same happens for all the shadows as I move the camera further away from the objects. This is not happening fi the light hits the objects directly.

If I use the Path Tracer, all the shadows are rendered out correctly. (see attached)

If I move the camera closer to the spheres furthest away, their shadow starts to come back. (see attached)

I’ve tried various settings for Culling with no success.

Am I missing any settings or is this a bug?

Thank you and I hope we will all have a better New Year!

2

I think I found where the issue was. It was on the viewport resolution. For some reason increasing GI ScreenSpace or general ScreenSpace did not help. Nor increasing the Samples Per Pixel to max 64 did not help. But viewport resolution helps!

3

As it usually happens I found another solution to the problem as I was looking for something else
https://static.xx.fbcdn.net/images/emoji.php/v9/t4c/1/16/1f642.png

There is another denoiser that I did not know about: r.DiffuseIndirect.Denoiser: 0
If I set this to 0 the shadows are much more accurate, but extremely noisy. It needs a RTGI Samples Per Pixel of 1024 minimum, which is to expensive even for Movie Render Que rendering.
So increasing the resolution and keeping this denoiser seems a good middle ground

4

Thanks for sharing that. I’ve encountered a similar issue with different settings for lighting. Now I’m going to try increasing viewport resolution for other shadow/light issues.