thermal image shader

[stevesideas]

Does anyone know how to create one ? I've tried using falloff (perpendicular/parallel) in a light material but it just doesn't work well. The closest I've got is to use falloff (shadow/light) but this only works when the camera and lights are under certain conditions. I'm trying with gradient ramp at the moment but not really getting anywhere.

[MoonDoggie]

I would do something similar to what you're doing to create the "backplate", images of subtle blue shifts and then create a FG layer with oranges and reds for certain "thermal objects". I'd use a falloff map on the thermal object material with bright red/orange in the perpendicular angle and light greens in the parallel angle.

[super gnu]

if you wanted to give it a bit more complexity you could use various ao passes to control the hue as well, maybe in combination with falloff and manual selection of "hot and cold" geometry. maybe also bring a zdepth mask into play as well. in any case, unless you wanna do something really funky with phoenix youre always gonna be doing something very approximate!

[joconnell]

Have you got an idea what it should look like? I'd use a gradient ramp with a rainbow set of colours and then set it to "mapped" mode, with a falloff map dropped into the source map slot. Or use the sample rate element!

[samuel_bubat]

A Falloff with shadow/light (as extra tex render element) is probabely the closets you can get.
The problem is, it offers only two colors. You could pipe it through a mix map where the mix amount
is a black white falloff shadow/light. Color one is red and color two is another falloff shadow/light with the colors green and blue. But it would require a lot of fine tuning
of the mix curves to get the desired result. An easier way is. Render out an extra tex render element also with shadow/light falloff. Open it in photoshop
and use image/adjust/gradientmap with red/green/blue as gradient color.. or whatever color you need. And another option, in case scanline or MR is an option
you could use "pseudocolor" exposure control.

edit: btw. If you do it like this you can translate light to heat. As brighter as hoter an object will be.
So you should not traditionally light your scene but add light materials or selfillu. maps
to objects intended to be hot.Objects that "radiate heat" into your scene.
If I recall it correctly radiosity was initally invented to calculate heat within radiators. But not sure if it follows the same math.

[joconnell]

An easier way is. Render out an extra tex render element also with shadow/light falloff. Open it in photoshop
and use image/adjust/gradientmap with red/green/blue as gradient color.. or whatever color you need. And another option, in case scanline or MR is an option
you could use "pseudocolor" exposure control.

Gradient ramp in mapped mode will do this too - it'll use a falloff map between black and white as a way of mapping all of the colour swatches you place along the gradient to different shades of grey!

[samuel_bubat]

Yep, you´re right, missed the part about the shadow/light falloff map in the source map.

[stevesideas]

Thanks for the tips guys. Sorry I've not replied sooner. I didn't actually explan that the thermal image is more like the police cam heli shots you get. So mainly white parts are hot and the clothing is darker but has lighter parts where they are more heated. I ended up tinkering with a falloff map for ages and managed to get something that the client is happy with.