Glass issue in the GPU mode

[Mousa_SA]

Hello,

I have exported an object from 3 Max as vrscene to SketchUp, and the issue is that the reflection of the glass is not Visible in GPU, note that it works fine in the CPU mode.

Kindly find attached file

[konstantin_chaos]

Hi Mousa,

Can you please re-upload the file.
I am not able to download it.
Thanks.

Konstantin

[Mousa_SA]

Hi Konstantin,

I have uploaded it to this link

Thanks

[konstantin_chaos]

Hi,

This time I got it, thanks.

The issue is actually not in the vrscene reference but the glass material itself.
I rendered the material in 3ds Max and there is the same discrepancy visible (GPU vs CPU):


I believe the root cause of this is the output correction of the Reflection and Opacity bitmaps.
Both have custom RGB Level specified:

This parameter seems to cause incorrect results on GPU.
I'll investigate further and possibly report this to the GPU team.

I'd also recommend you to keep things simple and avoid that approach if possible.
You can just set the opacity map value when you make the texture instead of correcting it after the fact.
Using the Opacity percentage in the material Maps section is another good way to multiply the result.
Another thing that you should avoid is using textures values that exceed 1.0 (255).
In the example material this was the case with the Reflections.
In order to get stronger reflection you can instead tweak the Fresnel IOR value.

I hope this makes sense.

Regards,
Konstantin

[Mousa_SA]

Hi Konstantin.
Thank you for your detailed reply, I will be sure to keep the workflow simplified, please note that this object is part of a model from Evermotion 3d models.

[konstantin_chaos]

OK, thanks for the heads up.
It seems that some of their shaders can be simplified for better performance, reliability and easier management.