[Radiance-general] mist

[Greg Ward]

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
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" <matanh@techunix.technion.ac.il>
> 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