[esp-r] Re: View factors using Raytracing

[Raghuram Kalyanam]

Thanks Jon for the valuable information.

Best Regards,
Raghu

> On May 24, 2017, at 3:41 PM, Jon Hand <jon at esru.strath.ac.uk> wrote:
> 
> 
> The method used is not MonteCarlo.  It is a mix of analytical techniques (e.g. detection of
> rectangular enclosures) and the grinding of points on surfaces and then geometric checks
> to see what 'other-points-in-the-zone' can be seen from each grid point.  It works for
> zone enclosures of arbitrary complexity (i.e. the polygons forming the room can  be
> of arbitrary complexity) with or without internal mass surface pairs.  I have tested it
> with rooms approaching 90 surfaces and with polygons up to 48 edges. In most situations
> we find the calculated view factors are quite accurate.  And yes the method is
> rather fast on modern computers.
> 
> Also the method allows for people to include MRT radiant sensors within zones
> and the viewfactors between such bodies and the room surfaces to be calculated.
> This allows position specific comfort to be assessed.
> 
> The only tweaks needed might be in the case of frames with small dimensions where
> the density of the grid would need to be increased.
> 
> The original work was done more than a decade ago but there should be a 
> publication in the ESRU web pages which describes the numerical approach
> in detail.  There are also comments within the code.
> 
> You could also have a look at the following web site for more information on
> ESP-r facilities:
> http://contrasting.no-ip.org/ESP-r_tour/Index.html
> 
> and the following web site for a comparison with other simulation tools:
> http://contrasting.no-ip.org/Contrast/Index.html
> 
> ________________________________________
> From: esp-r-bounces at lists.strath.ac.uk [esp-r-bounces at lists.strath.ac.uk] on behalf of Raghuram Kalyanam [kalyanam at rhrk.uni-kl.de]
> Sent: 24 May 2017 08:54
> To: esp-r at lists.strath.ac.uk
> Subject: [esp-r]  View factors using Raytracing
> 
> Hi Everyone,
> 
> I have quick question about how view factors are calculated using raytracing technique. Also raytracing normally takes lot of time, but in ESP-r it seems it is quite fast. Does this raytracing technique do the Montecarlo simulations like in Radiance or is it a different kind of raytracing?
> 
> I would be great if someone could throw some light on this, or any references i can go through.
> 
> 
> Best Regards,
> Raghu
> 
> 
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