Question about the visualization of a perforated material with a BSDF function

Dear @chris, I need help to understand one question about the BSDF modifier in the LBT.

I have created a BSDF xml file out from WINDOWS 7.7 for a perforated screen.
Hier the visualization of the file through the BSDF Viewer:

In a example, I have set a surface with a Radiance perforation.cal material and this is the result (so far everything ok)

in a another test, I set for the same surface/geometry, the BSDF modifier with the created xml file and this is the result:

I am not very experienced, but I thought to visualize with the BSDF also the perforation of the surface with relative scattering (but the surface with the BSDF looks transparent), instead I only notice a circular reflection around the window.

I would like to understand if I am doing something wrong.

re_viewbased.gh (86.9 KB)

Hier the xml file to download
https://fspit2storage.blob.core.windows.net/fspwinappblobs/20211122/0b38c72d-bfe2-4038-a3d6-658d6ff77ba8/PerforatedVenetianBlind.xml

Thanks in advance

I don’t think you’re doing anything wrong here, @Jorn.Gunner.Lande . It’s just that Klems BSDFs are pretty severe abstractions of real details so, when you render a BSDF like that, all that you are going to see are the patches of the BSDF.

In your case, all of the patches seem to be of comparable brightness, making it look like window is just a single value. Think of it like you’re taking all of those detailed perforations and then just converting them into an averaged material that has the same overall transmittance of the perforated one. This abstraction is probably good enough for some cases like evaluating the indoor illuminance but it’s probably not the best to evaluate things like glare.

Hope that helps.

Hallo chris, thanks for the reply.

using the xml file on the geometry that replicates the blinds gives me the same DGP-Value as when I analyze without the blinds.
Hier another example between blinds geometries with a perforation.cal material and blinds with the BSDF modifier.


What solution is better to see rendered also the scattering effect of the blind? recreate the perforated blind in Rhino and give it the BSDF?
I tried to do this, but the _Shade component after several hours don´t read the perforated geometry from Rhino.
Is not possible to insert the BSDF values directly into the mixfunc modifier?

As you wrote before, this is not a good case to evaluate Glare, but I would not have an error also for a Illuminance analysis?

Thanks and Greetings