Yet another volume confusion

[epilectrolytics]

During the testing of the new hybrid path engine I created this file

cube3.blend.zip

(244.84 KiB) Downloaded 150 times

in which I couldn't get the blue sky to show when using PathOCL.
But it shows in PathCPU and BiDir.
.



Dade told me it doesn't work because I didn't set a world volume, but when I do that (either the fog volume or a new clear volume) still I get no blue sky with PathOCL.

Could someone please show me how I get this to work?

[lighting_freak]

Hi,

That sounds like an not totally resolved thread I've opened some time ago:

viewtopic.php?f=4&t=820&p=8825#p8832

BR

[Dade]

Dade told me it doesn't work because I didn't set a world volume, but when I do that (either the fog volume or a new clear volume) still I get no blue sky with PathOCL.

The correct result is the one with grey sky, not the one with clear one. The sky is very far and scattering will make it very hard to see. The clear sky result is usually what you get by not assigning the world volume (I will check the scene when I'm back to my PC).

If you want a clear sky, just use a bounding "NULL" material box around the room with the "fog" volume. It should produce the clear sky.

It is like in real world:

- only dusty room => sky visible
- dusty room + fog => grey sky

[epilectrolytics]

That sounds like an not totally resolved thread I've opened some time ago:

viewtopic.php?f=4&t=820&p=8825#p8832

Thanks for that link, I'm going to read through it.

The correct result is the one with grey sky, not the one with clear one.

That would be the case if I used a world volume and no fog box and if I do so, indeed PathCPU and PathOCL show the grey result as expected.
The scene is meant to show a dusty interior with a rather clear sky, no atmospheric effect.

If you want a clear sky, just use a bounding "NULL" material box around the room with the "fog" volume. It should produce the clear sky.

But that's what I did in the file.
The room (walls etc) has thickness and the inside seen by the camera is the outside of the room geometry, but inside of the fog box.

What confuses me is that PathCPU renders differently than PathOCL, isn't that an OpenCL bug then?

[lacilaci]

While fooling around with caustics and volumes I got confused too..

I have a glass railing panels in a scene and their absorbtion is affecting the whole scene for some reason. Not sure if related

here's glass panel with 1m absorbtion distance

10absorbtion (notice sky remains dark/black)

100m absorbtion and sky looks normal(it's a unicolor background not actual sky) and windows use archglass not the same as railing panels.

[B.Y.O.B.]

@lacilaci Check if your glass sheets have thickness and if the normals are pointing in the right directions (outside).

[epilectrolytics]

That sounds like an not totally resolved thread I've opened some time ago:

viewtopic.php?f=4&t=820&p=8825#p8832

Seems like with the type of hetero scattering volume, the camera can see out of window.

Yep, that works!

But still PathCPU renders deeper blue than PathOCL.
Something's wrong with OCL here, but maybe something's wrong with homogenous volume too?

[wasd]

Setting camera volume makes no sense.

[epilectrolytics]

I made that a habit since I discovered that auto-detect is not stable through animations.

Render with hetero volume and a tiny little hint of blue:

[Dade]

Dade told me it doesn't work because I didn't set a world volume, but when I do that (either the fog volume or a new clear volume) still I get no blue sky with PathOCL.

I should have fixed the bug.