LuxCoreRender Forums

Hi Kintux, unfortunately i cannot save blender files because i'm not a blender user.
I can deliver only luxcore and obj files. But luxcore has also 3D max users so i'm probably not the only one which has difficulties to deliver a blender file.
For this reason the scene i so basic. It fucus only on this specific prolem so the debug is easier. Despite it's non orthodox modelling it behaves exactly every other scene i have. The walls without thickness do not disturb since the environment is pure black. There are no polygon intersections enywhere in the scene.
Moreover the problem is so simple that everyone who has blender can reproduce it in 30 seconds, 1 box, a plane and one spot light. You should notice the same bahviour.

Here i completetely removed the box
Bidir on cpu The shadow you see behind the glass is correct but the one you see directly projected on to the red object is solid, which is wrong.

Isted if you do the same using PhotonGI you should get the other behiaviour i described in my previous post.

Here is the scene for blender(blender 3.1.2 /blendluxcore 2.61): bidir
path

aha, bidir has too high PGI Glossines treshold set so no SDS paths now, results match (disregarding brightness)

bidir

path

more on...

BIDIRCPU can now use PhotonGI cache to render SDS paths

kintuX what version of blendluxcore are you using?
Making PGI glossiness threshold to zero doesn't change anything in version 2.61, also disabling PGI doesn't work either. Only in version 2.5 that Bidir doesn't work with PGI i get a correct matching result.

Luximage wrote: Sun May 01, 2022 1:45 pm kintuX what version of blendluxcore are you using?

I'm using 2.61alpha (homebuild) in Blender 3.2alpha on W10.

Luximage wrote: Sun May 01, 2022 1:45 pmMaking PGI glossiness threshold to zero doesn't change anything in version 2.61, also disabling PGI doesn't work either. Only in version 2.5 that Bidir doesn't work with PGI i get a correct matching result.

Oh, I didn't set it to zero, but 0.005 just lower than that of Red Disney Material - it's Blender merely showing 3 digits

Edited file attached.


PS.
Worth reading through some of PhotonGI cache thread.

Hello kintuX thank you for the file, the difference in your file is not the glossiness threshold but enabling caustic cache and setting glass shadow color to black not to white.
Some renders from your file:

In blendluxcore 2.5 bidir doesn't support photon cache

Luximage wrote: Sun May 01, 2022 9:46 pm Hello kintuX thank you for the file, the difference in your file is not the glossiness threshold but enabling caustic cache and setting glass shadow color to black not to white.

Indeed, and other changes...

Luximage wrote: Sun May 01, 2022 9:46 pm In blendluxcore 2.5 bidir doesn't support photon cache

So no SDSD paths. Results match and I'm lost - What's wrong again?

Yes kintuX you made quite a few changes to that file .
In blendlucore 2.5 using bidir you just need to make the glass shadow color white, it matches the result of version 2.61 using path where the glass shadow is also white and only photon cache enabled(light tracing and caustic cache disabled). In those two examples the glass is not visible at all in the red capsule.
The other two examples that match are both in 2.61 version with glass shadow color kept black ,first one bidir with photon and caustic cache enabled and the second one path with photon, caustic cache, light tracing enabled. But in those two examples there is still some glass visible in the red capsule. See the image below.

Thank you all for the effort to understand the issue.

Hi, i created also this scene which isolates the problem with physical sky or HDRI under BIDIR.

No obstacles of any kind in the window

Obstacle with black shadow


Obstacle with white shadow. I would expect the last scenes looking very similar to the first one, letting all direct sun and sky light in. Interesting is also the gradient artifact on the floor.

Please dade help us with this. It is truly important as you see because it strongly affects all interior scenes with natural light.

Attached the luxcore scenes and also the obj file