[Radiance-general] modeling trees in Radiance

[Greg Ward]

Yes, I should have thought about the square root -- good catch!

The trans type doesn't change with incident angle (unlike glass or dielectric), which is part of why I suggested it.  I don't know what's happening in Germán's case, but using a mixfunc with void and plastic is a perfectly acceptable approach.

As for varying the absorption using mist, a ball of mist might indeed have the desired behavior, as the absorption is an exponential function of the volume traversed using the mist material.

Cheers,
-Greg

> From: Christopher Rush <Christopher.Rush at arup.com>
> Subject: Re: [Radiance-general] modeling trees in Radiance
> Date: February 5, 2015 7:05:02 AM PST
> 
> I see Raphaël just pointed out what I was in the middle of typing about the square root transmittance correction. Also, keep in mind this will only be a very rough approximation for any measurements very near the tree, where rays passing through all parts of the tree get the same reduction even if they just glance the fringe of the sphere or other shape. In reality, rays passing through the outer fringes of a tree canopy would intersect with fewer leaves than those passing through the more substantial core of the tree (also depending on tree species).
> 
> I would love to here if anyone has a more ideal solution for modeling trees that is relatively accurate, and reasonable in terms of rendering time and use of RAM – in other words without modeling every single leaf. If it looked nice that would be a bonus. Is this a possible application for something exotic like mist? I’ve never even investigated mist so apologies if that’s a ridiculous suggestion.
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