[Radiance-general] Noise free rendering of simple sun/sky scene

[Claus B. Madsen]

Dear all,

I am new to this list .. and not all that experienced in using Radiance.

I have problems determining render parameter settings that will produce 
an (almost) noise free rendering of simple scenes illuminated by a sky 
dome and a sun disk. I want to have soft shadows from both the sky dome 
(180 degree source) and the Sun (0.53 degree source). My .rad file is 
listed below. I realize that both sources (sky and sun) are "white" ... 
thats not the issue ... I am just sending the simplest form of the types 
of scenes I wish to render.

I am rendering with these parameters, but the results are horrobly 
noisy, and I do not get soft shadows from the Sun:
rpict -x 640 -y 480 -ab 2 -aw 0 -dr 3 -dp 4096 -ds 0.01 -dj 0.6

I have the Rendering with Radiance book, but cannot really find a clear 
"how to" in terms of setting the parameters so that my picture comes out 
right.

Hope I am not offending anybody by posting such a simple problem.

Sincerely,
Claus

P.S. I am performing research in Augmented Reality and will be using my 
renderings in conjunction with techniques I have developed for 
estimating the Sun and the Sky radiances from images of real scenes. I 
will the render some simple geometry using Radiance and compose into the 
image with correct shading and shadows


------------------------------------------------------------------------------------------------------------
# Materials

void plastic white_matte
0
0
5 1.0 1.0 1.0 0 0



# Objects

white_matte sphere ball4
0
0
4 0.0 0.0 2.0 2.0


!genbox white_matte groundplane \
20 20 0.5 -r 0.08 | xform -t -10 -10 -0.25



# Illumination environment: a 0.53 degree diameter disk and a
# 180 degree skydome

# The Sun ... radiance set to provide unity irradiance for
# normal pointing right into the sun
void light sunradiance
0
0
3 14880 14880 14880


sunradiance source TheSun
0
0
4 -1 -1 1 0.53



# The Sky ... radiance set to provide unity irradiance for
# normal pointing right into the sky
void light skyradiance
0
0
3 0.159 0.159 0.159

skyradiance source TheSky
0
0
4 0 0 1 180.0
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