rendering large space with small detail

Hi,
Thinking about the difference between photorealism rendering and light
visualization related in RWR chapter 1, pag 4 and 5. I'd like to
elucidate some questions about this topic:
Doing so, ( procedures included below by example), is still a
phisically based simulation?
Is it a valid procedure to predict how natural light behaves inside this space?
Is it a valid method to get fast, acurate and predictive daylight calculation?

Anyway, I was frightened with plethora of variations and possibilities
to solve this problem.

thank you,

regards
Vangelis

···

as Rob said, bringing the light source closer to the scene is a good
start :wink: 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!

Hi Evangelos,

I'm a little confused by your email. Are you asking about the validity of things such as mkillum in a predictive lighting calculation? Because mkillum is most definitely a physically-based approach. As with any simulation method, the user and his or her assumptions factor into the equation, but using mkillum to essentially bring the direct calculation closer to the surfaces of interest, when properly used, is most definitely a valid procedure.

- Rob Guglielmetti

···

On May 20, 2009, at 9:19 AM, Evangelos Christakou wrote:

Hi,
Thinking about the difference between photorealism rendering and light
visualization related in RWR chapter 1, pag 4 and 5. I'd like to
elucidate some questions about this topic:
Doing so, ( procedures included below by example), is still a
phisically based simulation?
Is it a valid procedure to predict how natural light behaves inside this space?
Is it a valid method to get fast, acurate and predictive daylight calculation?