[esp-r] Re: question for ESP-r+Radiance users

[glbrune at polimi.it]

Def. Quota "Lars O. Grobe" <grobe at gmx.net>:

> Hi Gian Luca!

Hi Lars!

> Are you sure that you want to measure the radiance at a point, not  
> the irradiance?

I aim to the illuminance, but if I am able to get the radiance then I  
will be able to get the irradiance, luminance and illuminance. I just  
didn't want to get stuck in the fundamental operation.
>
> A rough idea, yes ;-) Type "rtrace -defaults", and you get the  
> default settings of the rtrace command, which will be appiled unless  
> you specify others on the command line.
>
> One of these settings is "-ab 0". This means, that only direct light  
> from light sources will be considered. No light reflected from other  
> surfaces, and also no light from glow-objects. So, if you have a  
> sunny sky, and your sensor is located outside, it will receive light  
> from the sun with -ab 0, but not from the remaining hemisphere which  
> is typically defined as glow. And if it inside, it will receive any  
> light unless it can directly see the sun.
>
> I would recommend Axel Jacob's Radiance tutorial as a start:
>
> http://www.jaloxa.eu/resources/radiance/documentation/index.shtml

It is very interesting indeed, as Axel Jacob's Cookbook.
>
> There are also some strategies described how to optimize  
> calculations avoiding too high -ab values, which slow down the  
> process (such as mkillum).

I am presently using "-ab 0.2" as a setting.

> And there has been a lot of development during the last year  
> especially in fenestration,

That's good news. Anyway, I'd like to keep the procedures as  
lightweight as I can.

> a look at the last workshop's slides at radiance-online.org may be useful.
>

Definitely.

> Cheers, Lars.
>
>

Thank you again. Cheers, Luca





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