[Radiance-general] Proxy geometry in the five-phase method

[Sarith Subramaniam]

The Daylight Coefficient 
<https://github.com/sariths/radTutorialFiles/blob/master/room/commands/2PM_DayCoeff.sh> 
and Three Phase 
<https://github.com/sariths/radTutorialFiles/blob/master/room/commands/3PM.sh> 
examples use a sky with 145 patches in which the sun accounts for 3-4 
patches. In these examples, the sky and sun are both represented through 
the "glow" primitive and the ray-tracing is stochastic. The additional 
steps in the Five Phase 
<https://github.com/sariths/radTutorialFiles/blob/master/room/commands/5PM.sh> 
example subtract out the direct component of the results from the 
glow-based oversized sun patches and replace them with replace them with 
accurately calculated direct sun-results. In this case, the sun is 
represented using the "light" primitive (implying a deterministic 
calculation) and is also more appropriately sized (0.533 degrees).

The exercise files also contain an improved version 
<https://github.com/sariths/radTutorialFiles/blob/master/room/commands/2PM_DDS.sh> 
of the Daylight Coefficient Method that features the direct-sun 
correction. I think the results from that calculation and the Five Phase 
calculation will be similar as they both involve the direct-sun correction.

The final part of the Five-Phase method requires Tensor-Tree BSDFs. The 
methodology for creating BSDFs from Radiance primitives is discussed in 
the genBSDF tutorial 
<https://www.radiance-online.org/learning/tutorials/Tutorial-genBSDF_v1.0.1.pdf>. 
If your glazing system is just a simple glazing comprised of something 
like "glass" or "trans", you can incorporate the glazing geometry 
directly. This process would be similar to what is discussed for the 
improved Daylight Coefficient calculation 
<https://github.com/sariths/radTutorialFiles/blob/master/room/commands/2PM_DDS.sh#L55-L73>. 



Sarith



On 12/8/2017 4:11 AM, WEI, Minchen [BSE] wrote:
>
> Hi All,
>
> I have questions regarding the proxy geometry in the five-phase method.
>
> I tried the tutorial using a room with a glazing (no venetian blinds). 
> The daylight coefficient and three-phase method can produce similar 
> results, but the five-phase method produce smaller illuminance values.
>
> I think the problem is coming from the “proxy geometry”. In my “proxy 
> geometry” I only included a glazing geometry with the transmittance I 
> used in the daylight coefficient method. Is that right?
>
> I looked at the proxy geometry included in Sarith’s tutorial which 
> included all the blinds, the glazing, and a BSDF (“blindsT4c.xml”) for 
> maxPoly and minPoly. How should I generate these BSDF if I have the 
> blinds?
>
> Thanks,
>
> Tommy
>
> --
>
> *Minchen (Tommy) Wei, PhD*
>
> The Hong Kong Polytechnic University
>
> (+852)-3400 3606 minchen.wei at polyu.edu.hk 
> <mailto:minchen.wei at polyu.edu.hk>
>
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