[Radiance-general] Rendering large space with small detail (small picture now attached!)

[Lars O. Grobe]

Hi,

as Rob said, bringing the light source closer to the scene is a good 
start ;-) You can do this in your case by using the gensky modifier for 
your horizontal skylight's glazing, instead of defining a glass pane 
plus an outside sky dome (I assume that you do not have any visible 
geometry that is seen through the horizontal skylight). The second is 
that in your case, it may be possible to define an mkillum surface in 
the vertical clerestory windows. This would produce an uniform illum 
source accounting for the external blinds and certainly help a lot to 
improve rendering times with acceptable image quality.

I would try to go with such a set-up. Replace the (vertical) clerestory 
glazing with a mkillum surface, the (horizontal) skylight glazing with 
the gensky modifier, and set higher ambient paramters as Rob suggested 
(and set a lower -ab, 2 or 3 should be fine with a good -av value!!!).

In case this is not enough - one COULD try to introduce a second mkillum 
surface below the internal shades, as these probably also are a bit 
tricky to calculate. In this case, one would place a gensurf-generated 
surface just below the internal shades, with a resolution to account for 
variations in the structure (I would try something like 4x4 from what I 
see on the image), which will be invisible, but replace all ambient 
calculations on top of the internat shades by 4x4 illum sources. This 
would lead to a very simple scene, with very short rendering times and 
virtually no noise. BUT - first try the other options!

CU Lars.
-- 
Lars O. Grobe (Mr) :: Research Fellow, Solar Energy Research Institute 
of Singapore SERIS :: National University of Singapore :: Block 4 
Engineering Drive 3, #E4-01-01, Singapore 117576 :: 65-6516 5816(Tel) :: 
65-6775 1943 (Fax) :: serlog at nus.edu.sg (E) :: www.seris.sg (W) :: 
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