Blackbody spectrum as a color ((a)gain)

[CTZn]

Early was it possible to assign a blackbody spectrum to a color parameter, and that provided us with the ability to generate a wide variety of tinted whites.

This doesn't work anymore, it seems like the blackbody is forced to match the camera's white point. Could we get that feature back please ?

[fused]

Early was it possible to assign a blackbody spectrum to a color parameter, and that provided us with the ability to generate a wide variety of tinted whites.

This doesn't work anymore, it seems like the blackbody is forced to match the camera's white point. Could we get that feature back please ?

Hi Adam,

not sure what you mean exactly.

Something like this was (and still is) possible with base emission and emission, but I can't recall anything else like that.

Cheers!

[CTZn]

I think that the feature was removed with or just before Indigo 2.0, not much later anyhow. The blackbody gain was ignored, but the temperature changes were reflected in the albedo.

In fact, the possibility was never mentioned so it had to fade away at some point

[fused]

I think that the feature was removed with or just before Indigo 2.0, not much later anyhow. The blackbody gain was ignored, but the temperature changes were reflected in the albedo.

In fact, the possibility was never mentioned so it had to fade away at some point

I really can't recall anything like that, sorry

[CTZn]

I think that the feature was removed with or just before Indigo 2.0, not much later anyhow. The blackbody gain was ignored, but the temperature changes were reflected in the albedo.

In fact, the possibility was never mentioned so it had to fade away at some point

I really can't recall anything like that, sorry

Would you like a blackbody spectrum defining warmer or cooler albedos ? To have. It. Back

That's because it was confidential that it faded out I'd bet. Ono must have implemented it then it was removed back then. Reflectors, walls, test scenes, it's a nice way to tweak whites.

[CTZn]

It just popped to my eyes when I was staring at lape's render: the peeble colour can be brought down to a variation of their albedo as a temperature. Then comes the gain, clamped as should.

http://www.indigorenderer.com/images/we ... =_original

[galinette]

Just take this and make a wavelength dependant shader:

http://en.wikipedia.org/wiki/Planck%27s_law

Just normalize the law by its maximum value, which is quite easy to approximate (wavelength at maximum is proportionnal to temperature, formulas can be found somewhere)

[galinette]

By the way, I don't even think a shader is necessary. You can use a blackbody as an albedo spectrum in igs code. It's not normalized, so you have to normalize by setting the gain to the appropriate value

Other way, is calculating the white point x/y from temperature (the formulas are easy to find) and convert to XYZ then RGB

Etienne

[CTZn]

Just take this and make a wavelength dependant shader:

http://en.wikipedia.org/wiki/Planck%27s_law

Can not read maths, thanks. May not want to.

By the way, I don't even think a shader is necessary. You can use a blackbody as an albedo spectrum in igs code. It's not normalized, so you have to normalize by setting the gain to the appropriate value

Ah this is it, the gain was normalised for albedi back then.

Other way, is calculating the white point x/y from temperature (the formulas are easy to find) and convert to XYZ then RGB

I've got one in python around.

Etienne

Thank you !