"Pink Elephant" Saturated Color Absorption Noise

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"Pink Elephant" Saturated Color Absorption Noise

Postby Meelis » Thu Apr 26, 2012 12:20 am

Hi :)

Let's say i choose some RGB color from LuxBlend color picer and set abs at depth to 0.002.

It comes out for me as a news it's big no no if from 3 of the R, G and B values one value is 0 and another is 1.
Result is pink noise with material that looks like that:

Code: Select all
MakeNamedVolume "Blue" "clear"
   "float fresnel" [1.458999991416931]
   "color absorption" [34538.77475441 312.70161396 0.00000000]

MakeNamedMaterial "Blue"
   "bool architectural" ["false"]
   "bool dispersion" ["true"]
   "string type" ["glass2"]


Now i replace 0 with 0.05 and 1 with 0.9 or 0.95 and all is fine. Absorption looks like that now:
Code: Select all
   "color absorption" [802.50032607 209.59308668 52.68026857]


So my idea was in that we limit out 0 and 1 values from color picer.

I do get some color elephants even with one value beeing 0 or 1.
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Re: "Pink Elephant" Saturated Color Absorption Noise

Postby J the Ninja » Thu Apr 26, 2012 1:03 am

Well, when you think about it, it makes sense. You wind up with a volume that transmits some wavelengths perfectly, and others it blocks completely.

Unfortunately, I don't think we can define min/max values for color. Locking 1.0 would also prevent you from having a volume with 0 absorption, which I've found is useful sometimes, either with glass2 or using a homogeneous volume. (sometimes you just want scattering or IOR without absorption. Not really correct, but useful)
-Jason

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Re: "Pink Elephant" Saturated Color Absorption Noise

Postby Meelis » Thu Apr 26, 2012 2:12 am

J the Ninja wrote:Well, when you think about it, it makes sense. You wind up with a volume that transmits some wavelengths perfectly, and others it blocks completely.

Unfortunately, I don't think we can define min/max values for color. Locking 1.0 would also prevent you from having a volume with 0 absorption, which I've found is useful sometimes, either with glass2 or using a homogeneous volume. (sometimes you just want scattering or IOR without absorption. Not really correct, but useful)


Good point.

Perhaps we can add tiny itty pitty pinke elephant icon by 16x16 or 32x32 pix to color picer,
in case wnen 0 or 1 is choosen then pink elephant icon will appear MAGICALLY from nowhere :D
For newbies ;)
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