Gaussian Spectrum

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Gaussian Spectrum

Postby DinoMuhic » Fri Jan 29, 2016 1:05 pm

DinoMuhic Fri Jan 29, 2016 1:05 pm
Has anyone a good explaination what this node does? I just can't wrap my head around it. How and when is it supposed to be used?

Can anyone link me to a throughout explaination?

Thanks a lot.
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Re: Gaussian Spectrum

Postby brasco » Fri Jan 29, 2016 2:53 pm

brasco Fri Jan 29, 2016 2:53 pm
Hi Dino,

Been looking into it myself, and I think in basic terms it's a way to give you colour based on realistic spectra.
Someone please correct me if I'm wrong here.

It's best described in images and a (very badly drawn) graph :)

Image


So inputting those values (roughly) into the GS node (wavelength in μm not nm like the graph) and putting it in the Spec channel (Index = 1) gives you this:

Image

Increasing the width value will widen the spectra included and eventually desaturate to white.
You can of course add variation to the wavelength to give you varying colours:

Image


cheers
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Re: Gaussian Spectrum

Postby bepeg4d » Fri Jan 29, 2016 4:35 pm

bepeg4d Fri Jan 29, 2016 4:35 pm
Hi,
perfect explanation, brasco ;)
In simple words we could consider it like another way to input colors. Since Octane converts the RGB colours to a spectrum, using this node, the color is not converted. It works in a similar way as the HSV space where the Hue is given by the Wavelength, the Saturation by the Width value (in the opposite direction, lower values will give more saturated colors), and finally the Value is given by the Power value. You can use it in any color input pin, for example in texture emission node gives much better results compared with a classic RGB node ;)
ciao beppe
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Re: Gaussian Spectrum

Postby ratata » Fri Jan 29, 2016 6:31 pm

ratata Fri Jan 29, 2016 6:31 pm
Hi, can you elaborate on this

"for example in texture emission node gives much better results compared with a classic RGB node"

what do you mean by better results? accurate color? faster render?

Thanks

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Re: Gaussian Spectrum

Postby Yambo » Sat Jan 30, 2016 8:37 am

Yambo Sat Jan 30, 2016 8:37 am


wow thanks beppe! using the gaussianspectrum for colored emission is wonderful solution. i will definitely remember it.

:)
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Re: Gaussian Spectrum

Postby DinoMuhic » Sat Jan 30, 2016 6:43 pm

DinoMuhic Sat Jan 30, 2016 6:43 pm
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Re: Gaussian Spectrum

Postby ratata » Sat Jan 30, 2016 8:01 pm

ratata Sat Jan 30, 2016 8:01 pm
Thanks for the links!
http://www.twitter.com/sandidolsak

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Re: Gaussian Spectrum

Postby MildMustard » Mon Nov 07, 2016 9:38 am

MildMustard Mon Nov 07, 2016 9:38 am
Anyone know how to find the width and power of the wavelength on a given metal, like Copper on http://refractiveindex.info/?shelf=main&book=Cu&page=Rakic/ ?
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