On 5/24/20 10:22 AM, William F Pokorny wrote:
> On 5/21/20 8:32 AM, William F Pokorny wrote:
...
> 
> The finish irid feature assumes a 0-1 distribution and does some math to 
> get a zero centered, -1 to 1 one for further calculation. It hard codes 
> the turbulence parameters and has omega at 0.5. This feature has some 
> other issues like lack of ability to scale relative to the incoming 
> coordinates which will make it tricky to get something which always 
> works with respect to scene dimensions. The documentation also mentions 
> irid_amount and I don't see it anywhere in the calculations... I think 
> given numerical accuracy there should be some >=0 clamping to not 
> sometimes get negative thicknesses... Anyway work to do here.
> 

Attached an image up the updated irid code running with the fixed 
Turbulence(). I also added the clamp to prevent the film thickness from 
going below 0.0 and one of our demo scenes hits this clamp. See the 
lower right sphere in the middle set. Less colorful result but I think 
correct. There is no film there.

I also tried for a matching fudge factor to match the breadth of the old 
Turbulence() distribution. Cannot match previous precisely, but not bad 
in my view.

Bill P.

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