Infrared rendering

[Mats_O]

Hi,

How can we render images similar to images from a infrared camera? We need to do it in a physically correct way and not in post.

[Joelaff]

Do you mean like infra-red film? If so, color or black and white?

Or do you mean like a FLIR type camera for seeing heat maps?

I would think the film look could be achieved with shaders that mimic what the surfaces look like on infrared film (color or B&W). The heat map look could be done with texture maps literally setting the values of the heat on the surfaces. This could be done with simple grey values that then get remapped to pseudo color in post (which is exactly what a FLIR does).

[Mats_O]

Neither, I think.... More if the renderer can use IR wavelengths in its calculations. Then the result should be mapped into something visible, like the different options you mention.

[Joelaff]

I guess I have to ask, what are you trying to achieve? If this is for some sort of technical engineering endeavor then VRay is probably not your tool. If this is for artistic purposes, what is the look you want?

Being very close to the wavelength of visible light IR behaves very similarly. Lenses focus it slightly differently, just like they focus red and violet light differently. (See apochromatic vs achromatic lenses). Remember the red line on manual focus lenses that was used to compensate for IR?

Nevertheless, the look is pretty much the same. You would still have to surface your objects based on how they react to light in the IR frequencies.