I need to visualize glazings with different light transmittance values (VT: visible transmittance, eg. 0.35, 0.55, 0.65)
Where in the glass window neutral material can I ajust these settings?
If I understand you right than refraction color should work for you.
Would be great, if Chaos could integrate some of these real world architectural glass types into the library.
Can confirm, this is done entirely through the Refraction color (use the Color Space: Rendering option of the V-Ray color picker).
The formula you are looking for is refractionValue^sheetsCount = lightTransmittance
Solved for the refraction value and a target light transmittance:
refractionValue = lightTransmittance^(1 / sheetsCount)
Sheets count is essentially each surface which refracts rays - a single glass pane has 2 sides (front/back).
For example, a simple glass pane with the transmittance you mentioned should be set up in V-Ray with approximate Refraction color of RGB: 0.59, 0.74, 0.81
Notified my colleagues from the Cosmos team about your request.
Kind regards,
Peter
Hi @Peter.Chaushev ,
This is something I’m trying to figure out too. Could you please explain a bit more how your formula works? I don’t understand the meaning of the ^ symbol.
And should the results of your formula be entered with Linear Numeric Values turned on or off?
I could be wrong, but I think the values that @oconv wrote in their original post (0.35, 0.55, and 0.65) might just be examples of different Visible Light Transmittance values, rather than a set of RGB values.
In the architectural glass industry ‘Visible Light Transmission’ is usually just a percentage value for each product.
I had hoped that representing VLT values accurately would be as simple as copying those values to the Refraction brightness, but the results I’m getting are a lot darker than the actual glass.
For example, normal glass with almost no tint is described in the glass industry as having VLT values in the 70-80% range. In the attached reference chart I made in V-Ray, normal architectural glass looks closer to 95% refraction.
Any advice you can offer would be most appreciated.
