(Open, Fixed) [VGPU-5948, HOU-3308] GPU fail with nested dielectric

[gagui]

Hello.
have a scene of a bottle full of water. I made the models to real scale, so this bottle is about 20 cm tall.

The geometry of the water overlaps the inner bottle to have a nested dielectric refraction. When I render the scene in CPU mode, it renders as expected, but in GPU mode, the nested dielectric doesn't appear and it's like there's nothing inside the bottle.
I think it has something to do with some sort of scale threshold that GPU mode applies because if I scale the scene like 10 times it seems to render just fine.

I attached the scene in case you want to take a look at it.

[tsvetomira.girginova]

Dear gagui , hello.

Looking at your file now. Overlapping may cause some issues, but let's see.

Could you also define the exact used GPU type and currently installed driver version?
Highly appreciated it will be.

Best regards,
TS

[gagui]

Hi.
Both RTX and CUDA modes fail.

My installed driver is NVIDIA Studio 516.93

[gagui]

Dear gagui , hello.

Looking at your file now. Overlapping may cause some issues, but let's see.

Could you also define the exact used GPU type and currently installed driver version?
Highly appreciated it will be.

Best regards,
TS

As far as I know overlapping is needed to have proper nested dielectrics.

[tsvetomira.girginova]

Hi again.

Interesting scene indeed. Thanks for sharing!
Some internal bugs were found and now are under investigation.
For now overlapping isn't charged as guilty.

The Fog color is differently calculated, we will handle this one.
I noticed that the .fbx object is very small. If you insert basic geometries like cube, sphere etc. they should be scaled to 0.1 to correspond the bottle.
So, units and scaling are involved. Could you share where the .fbx is exported from (if this information is known)?

Keep in mind that the effect of the fog color depends on the absolute size of the objects and is therefore scene-dependent.
I will investigate more and keep you posted.

Thanks for the challenge!

[tsvetomira.girginova]

In general we could summarize that when the bottle's height is around 20cm in GPU mode (both CUDA and RTX) Fog color is differently applied - no matter if there is water inside (overlapping) or not.
This is logged for further investigation to our dev team with VGPU-5948 number.
The concomitant founded bug about applying Fog Color (HOU-3308) is already fixed, but to render properly the bottle in the wanted size in GPU mode the VGPU-5948 fix is needed too.

You will be notified when it is ready and out for testing.
Thanks once more for reporting.

Enjoy the weekend.

[gagui]

Hi Tsvetomira!

Any news on this? I'm using vray 6 now and I can see some improvements but still not 1:1 match between CPU and GPU.
One thing I can notice now is if I render only the plastic bottle without the water it renders the same in GPU and CPU and if I render only the water without the bottle it renders the same too. Only when I render both bottle and water is when I get different result.

[tsvetomira.girginova]

Dear gagui, hello.

Excuse me for the delayed response.
Yes, the issue isn't fully resolved as you have noticed.

You will be notified by any further progress.