Tricky Lighting possibly volumetric Caustic Effect -- visibility through mirror

[davision]

I have a challenging effect to create. I need to show the visibility "cones" provided by some vehicle mirrors.

I can certainly just look through the mirrors from the driver's eye to show what can be seen BUT I'd also like to show what is visible from an external point of view what the mirror shows. So if I'm outside the vehicle, I'm imagining a volumetric type of light which is cast by using a light originating at driver eye position and bouncing it off the side view mirror.

Is this possible?

I remember many years ago, Vlado had posted some interesting refraction tests -- I believe he was passing a light through a prism, and showing the dispersion or reflection angles within the prism. It basically looked like volumetric caustics but I don't know if that's actually what he was doing.

Basically I'm trying to create a "light volume" or some sort -- that defines the edges of what this mirror can see as seen from outside the vehicle. I don't imagine there's an easy solution, but is there any solution.

[Raven]

I would build it with geometry, scriptspot has a few ray casting tools that create ray cast splines so you could use that define where your geometry needs to be.