On 2017-04-13 02:10 AM (-4), clipka wrote:
> The `ior` parameter is computed so that when used without dispersion,
> you get the correct refraction angle at what is typically the peak
> brightness (yellow, about spectral line D) (1).
>
> The `dispersion` parameter is computed so that you get the right
> difference in refraction angles between the red and violet ends of the
> spectrum (2).
>
> POV-Ray, on the other hand, naively presumes that the refractive index
> of dispersive materials is a linear function of wavelength varying from
> IOR-CONST to IOR+CONST, implying that IOR is specified at the wavelength
> halfway between red and blue, meaning you can't get both properties (1)
> and (2) at the same time.

This is very helpful to know.  Thanks!

Post a reply to this message