mist

hallo to u all!!!
im a graduate student dealing with agricultural eng. and i found radiance
very usefull in determining optimal tree prunning.
my problem is such. i found from field experiments extinction of light into
the canopy (avocado in my case) and i was told using the "mist" material i
could model it on radiance.
does any one have experince or know how to turn an extinction formula
( i.e. I=Io*exp(-0.5x) x being the distance) into mist parameters?

thx
matan

Hi Matan,

The first three arguments to the "mist" material type are the extension coefficients with respect to distance. In other words, you can plug these values into a mist volume directly, like so:

void mist avocado_canopy_mist
0
3 .5 .5 .5

!genbox avocado_canopy_mist avocado_canopy 50 50 6 | xform -t 0 0 10

The above would place a 10-meter thick canopy that is 50x50 into your scene. I have no idea what you actually want, but hopefully this will set you in the right direction. If you want to see light scattered from this canopy, you need to add the names of the sources as string arguments to the mist material. See the Radiance reference manual for details:

http://radsite.lbl.gov/radiance/refer/ray.html#Materials

-Greg

···

From: "matan" <[email protected]>
Date: Tue Nov 11, 2003 2:39:23 AM US/Pacific

hallo to u all!!!
im a graduate student dealing with agricultural eng. and i found radiance
very usefull in determining optimal tree prunning.
my problem is such. i found from field experiments extinction of light into
the canopy (avocado in my case) and i was told using the "mist" material i
could model it on radiance.
does any one have experince or know how to turn an extinction formula
( i.e. I=Io*exp(-0.5x) x being the distance) into mist parameters?

thx
matan

matan wrote:

hallo to u all!!!
im a graduate student dealing with agricultural eng. and i found radiance
very usefull in determining optimal tree prunning.
my problem is such. i found from field experiments extinction of light into
the canopy (avocado in my case) and i was told using the "mist" material i
could model it on radiance.

Hi Matan,

You're using RADIANCE to model *avocados*? Now that's resourceful!
I'll bet a lotta fellas around here would rather model veggies and fruit than some bloody big buildings... :^)

does any one have experince or know how to turn an extinction formula
( i.e. I=Io*exp(-0.5x) x being the distance) into mist parameters?

In this case 0.5 would correspond to the coefficient of extinction specified with the MIST primitive or with the -me option.

See ya!

--Roland

···

--
Roland Schregle
PhD candidate, Fraunhofer Institute for Solar Energy Systems
RADIANCE Photon Map page: www.ise.fhg.de/radiance/photon-map

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