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How to create retro-reflective material for daylighting simulations?

asked 2023-07-24 15:09:28 -0500

architect210's avatar

updated 2023-08-01 06:44:53 -0500

Hi, is there anyone already worked with retro-reflective materials? We want to simulate them however, I assume that energy plus (simulation engine) considers only specular reflection and thus thinking if there is anything else that I'm missing when creating a retroflecting radiance material. Thank you for your time! Maria

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answered 2023-07-26 11:20:23 -0500

updated 2023-07-26 11:21:15 -0500

If you have a function describing the retroreflective behavior of your material, i.e., a BRDF, then you can use this function with bsdf2klems or bsdf2ttree to create an XML file that Radiance can use in its simulations. For example, here is a command to create a retroreflective material with a Gaussian lobe:

bsdf2ttree -t3 +for +back -e 'R:.75;S:.05' -e 'Gauss(u2):exp(-u2/(2*S*S))/(2*PI*S*S)' -e 'retro(ix,iy,iz,ox,oy,oz)=if(iz*oz,R*Gauss(1-(ix*ox+iy*oy+iz*oz)^2),0)' retro > retro.xml

To vary the total reflection, change the R constant. To vary the width of the lobe, change the S constant, which is in radians. (Note that single-quotes must be replaced by double-quotes if you are running under Windows.) The Radiance BSDF material is then used to apply this during simulation.

I hope this is enough to get you started.

Best, -Greg

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Dear Greg, thank you very much for your help!:)

architect210's avatar architect210  ( 2023-07-31 03:19:48 -0500 )edit

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Asked: 2023-07-24 15:05:57 -0500

Seen: 77 times

Last updated: Aug 01 '23