POV-Ray : Newsgroups : povray.advanced-users : Raytracing theory in Povray : Re: Raytracing theory in Povray Server Time13 Jun 2024 18:36:32 EDT (-0400)
 Re: Raytracing theory in Povray
 From: Alain Date: 10 Mar 2018 12:22:56 Message: <5aa41470\$1@news.povray.org>
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Le 18-03-09 à 09:45, muyu a écrit :
> Hi,
>
> In Povray, the optical properties of each surface can be set by ambient, diffuse
> and specular. This is very flexible but only single value is allowed over
> color-channels. As a matter of fact, the optical properties of object often
> differs over wavelength or colors. I am wondering what's the assumption in
> Povary to deal with this. It will be great if you could recommend a reference to
> describe the raytracing theory used in Povray. Thanks a lot in advance.
>
> Best regards
> Shouyang
>
>
ambient and emission can use a colour vector.

diffuse set the % of incoming light that get diffused by the material.
Use a float. Using a colour vector here is not physically correct, use
the pigment.

The pigment control the tint of the material. Use a colour vector, but
you can use a single float for grey levels.

reflection control the amount of light that get specularly reflected.
Use a colour vector or a single float. Can be set to use the fresnel law
where the amount of reflection is dependent on the IOR of the object and
the angle of incidence, or metallic where the pigment affect the colour
of the reflection.

specular and phong control the highlights. Use a float. Adding metallic
make the highlight take on the colour of the pigment.

The material can be more or less transparent. Controlled by the filter
and transmit optional components of the pigment.

Most transparent object should have an interior statement to set it's
ior, and optionally it's chromatic dispersion strength. When an object
have an ior, total internal reflections are taken care of automatically.

A transparent object can affect the colour of light going through it
using light fading, also set in the interior block.
Such an object can also be filled with some media that will greatly
affect it's appearance.

You can use SSLT by adding "subsurface integer, integer" in the