Eevee - Irradiance and shadows artifacts


#1

I´m facing with some artifacts that I cannot seem to solve, any ideas on what is the best workflow to follow in these cases?

In this picture check the artifacts in the irradiance volume, there are some probes that are weirdly high in brightness and I´m not sure why, also check the upper part of the box, near the ceiling, remember that brightness in the corner:

Now check what happens with that corner if I lower the camera:

The settings for the irradiance volume are 256Px as cubemap size, no probe is inside the walls, the diffuse occlusion is a 32px,

In those pictures there is no AO, Screen Space Reflections or any other effect apart from the Irradiance Volume.

This is a weird effect because it gives some weird light leaks even when no probe is in the outside of the room or inside of the walls, so it makes it very hard to achieve a clean interior lighting.

I´m sure this can be solved because there are others that are doing some archviz and don´t have this problem.

Solutions and ideas please?

Cheers!


#2

On thing I´ve noticed, if I increase the thickness of the wall to an absurd amount, that light leak dissappears (but the irrandiance volume weird brightness it´s still present):

Any idea why?

Cheers!


#3

Ok, I will autoanswer one thing for future reference:

The problem with the light leak was a problem with the sun light, so I managed to get rid of leaking by raising some paramenters, Exponent from 2.5 (default) to 10 and Bleed Bias to 1.0 (from 0.0 default), but I´m not sure if this last one is doing something because there is no difference when I change it back to 0.0

Now, the irradiance volume weird brightness is still present.

And I´m not sure what is causing this.

Also another artifact I can see when we have a lot of probes (just to gain detail in lighting) is that in the walls the probes leave some kind of artifact, and I can´t seem to get rid of it:

Here is the same picture but wihout the visible probes:

image

You can see a pattern there, and I don´t know how to get rid of it.

Cheers!


#4

If I lower the amount of probes, I get weird artifacts, the same patter artifacts but way bigger with straight lines visible, and also some artifacts in the corners:


#5

Anf finally, if I rais the amount of probes a lot, I just cranck up the problems:

And here is the picture without visible probes:

Uploading: image.png…

More pattern and more weirdly brightness probes.

Any solution for this?

Cheers!


#6

well isn’t that just a natural limitation of this system?

I mean its cached lighting on a grid, and your wall is so big it gets influence by many probes, and it just interpolates between each probe. So you end up having this stepping problems.

the bright spots look like these sample from bright areas too - you might get rid of it if you move the probes a bit? or change the probe radius?

sorry i have not played with this in practice so I dont know which other settings might exist.

But after all this looks like a classic realtime lighting problem…


#7

Yes, it´s possible, but I´m sure there should be some tricks to avoid or at least to minimize this, because I doubt behind the probes everything is a simple sphere interpolation.

On the other hand, I don´t understand the bright probes, I would like to know WHY are they happening, to try to avoide them, if I move the probes maybe those exact probes will not be bright, but others may be, and I would like to know why is that happening :slight_smile:

Thanks for the answer!


#8

Be sure to read the documentation first.

I suspect the bright spot are caused by the near clip distance of the grid.
The non smooth interpolation can be tweaked by using the Irradiance Smoothing slider but it will introduce bleeding.


#9

Hi, this is something related to irradiance volume but in my opinion has to do with object or geometry data. I noticed that in the demo archviz scene there is lack of color bleed. Once I joined floor object to the newly created geometry in the current daily build of blender, in this case the plane, color bleed seems to work fine (notice the bleed on the gray chair, second image is with more prominent color, to illustrate the problem better).



Scale on both objects were at 1.0,1.0,1.0. So I guess there is some other property which might be hidden from the UI, that affects the behavior of the light bounce from the object? I know that probe objects are in the scene from the more heavily development phase of blender, so in the next image I replaced old irradiance probe with the new one. Bounce strength and hue changed a bit, but the problem of the lack of light bleed persists. Appending this geometry to the new blender scene doesn’t solve the issue.