Problem with lights behind glass

[luca_militello]

Hi, with the latest available version of Vray for Ketchup for Mac Studio Ultra, I have a problem with the light source not being displayed when placed behind glass.
I attach the images in the file, the glass material is taken from Chaos Cosmos and the light settings are normal.
Vray version is hotfix 3, Sketchup version 2023.

Link:https://we.tl/t-cCz8tOoJDi

Many thanks

[natalia.gruzdova]

Hello luca_militello,
This is a known issue with Directional parameters due to a simplified directional distribution. The light is forced only in the forward direction, so the plane appears dark when viewing it from the side or through refractive\reflective materials.
We are working on possible improvements, you are welcome to check this thread for more details.

As a workaround you can make your light source you want to make Directional invisible and:

• Create a duplicate light source with 0 directionality, low intensity and leave it visible - this will be the one that is seen through the glass. You can disable Affect Diffuse so this duplicate does not contribute to the illumination.
• Or apply Emissive material to the ceiling fixture.

I have attached a simple test scene with these options.

[natalia.gruzdova]

Hello luca_militello,
Thank you for your post and for the provided examples.

Please try changing Directionality to the values between 0 and 0.3 under Rectangular Lights settings and let me know if it works for you.

[luca_militello]

Hello Natalia,
Thanks for the advice, I actually did the test and it works.
Can I ask you how come I have to change this parameter?

Thank you.

[natalia.gruzdova]

Hello luca_militello,
This is a known issue with Directional parameters due to a simplified directional distribution. The light is forced only in the forward direction, so the plane appears dark when viewing it from the side or through refractive\reflective materials.
We are working on possible improvements, you are welcome to check this thread for more details.

As a workaround you can make your light source you want to make Directional invisible and:

• Create a duplicate light source with 0 directionality, low intensity and leave it visible - this will be the one that is seen through the glass. You can disable Affect Diffuse so this duplicate does not contribute to the illumination.
• Or apply Emissive material to the ceiling fixture.

I have attached a simple test scene with these options.