Light leak at edges inside room and irradiance volume issues


(cekuhnen) #1

Hi today in class we experimented with eeVee in interior spaces and encountered a lot of light leaks along edges etc.

some floor related issues we were able to fix with the contact shadow option.

others like in the image remained.

an regarding the irradiance volume yesterday I read the room should be inside the space.
when I do this I get however GI light glow artifacts on the wall (marked with the arrow)

any tip how to improve this?


(Blender Foundation CERTIFIED TRAINER) #2

Subscribing. This happened to me yesterday. A perfect cube, just remove 1 face, I get this same result.


(cekuhnen) #3

I think the faces in my case where inverted.

with a solid model the light leak is upper right corner now


(hypersomniac) #4

Could you share the file? I think this is specular light leaking but not sure.

Also yes, adding thickness to objects mitigate the shadow map “peter panning” artifact. Contact shadows are here for that reason but they might not work when computing the light cache.


(cekuhnen) #5

here is the file
https://drive.google.com/file/d/14Fe7ckYtK6rFhbdz8hhuNoRELuqGPwBj/view?usp=sharing

I noticed that the face was flipped but with flipping and thickness it still has issues upper right corner now.

I think it is a specular leak

when Turing the specularity off it is gone


(Emir Sinan GĂĽrlek) #6

Could you please elaborate on this? Where to find that specularity value to turn off? I believe we are not talking about material specular value (because changing it doesn’t cause any leaks etc.).


(cekuhnen) #7

The specular reflection of the material principled shader.


(Emir Sinan GĂĽrlek) #8

As I said changing material specular value doesn’t cause any light leak. Here I set specular to 1 for all materials in the scene and there is no leak. Am I missing something here?


(cekuhnen) #9

Look at your result look at my result - same scene.
MacOS build. see my top right corner has a bright edge?


(Emir Sinan GĂĽrlek) #10

That’s strange.
Maybe It’s the Blender version, which one are you using? Here is mine:
image

Might there be some differences between MacOS and Windows @hypersomniac ?


(jendrzych) #11

It seems that the Specularity is the problem.
Windows 10 64 bit
8alpha2

Irradiance baked, spec. = 0.5:

No irradiance, spec. = 0.5:


(warnotte) #12

I was looking this thread and decide to test something.

And find something similar + strange bug with shadow or i don’t know what.

I you move the light you’ll see that if it goes closer or far away from the cube the artifact appears or not.

LightLeaks.blend (98.2 KB)

Blender version :

Ver


(jendrzych) #13

Yep - I’ve the same results. The light’s axis has to be pointed in the examinated meshes edge, though. Type of light doesn’t matter, it gets even worse with the Sun light. Solidifying the mesh does not help either.


(English is not my native language) #14

Lamp > Shadow > Exponent: Bias for reducing light-bleed on exponential shadow maps

Exponent=9 take some effect for this point lamp.


(jendrzych) #15

It doesn’t make light look like it should - leaks gets sharp edges, that’s all.


(cekuhnen) #16

Darn issue - in class yesterday we started with sun light for an interior view and my demo was a disaster hahaha


(jendrzych) #17

Yesterday I was about to make a rough concept visualisation of a building expansion for my client. After some wrestling with light leaks and light blotches, I sticked to a cardboard Sketchup model… Pity…


(cekuhnen) #18

it seems when using area lights in windows this works better


(English is not my native language) #19

Another attempt with another configuration for that specific scene:

Some strange reflections on walls may come from the used light probes, with which I have not experienced much.


(artell) #20

Shadow maps can be pain to setup, however there are ways to fix it:
-Solidify the meshes
-Shorten the “Clip Start” distance
-Decrease the Bias
-Increase Exponent
-Play with the Contact Shadows if necessary

I’m not sure @hypersomniac can improve it that much, unfortunately shadow maps have issues in all real time engines such as Unity and Unreal.