This is the case for all objects that involve the solution of a cubic or quartic polynomial. There are analytic mathematical solutions for those polynomals that can be used. Lower order polynomals are trivial to solve while higher order polynomials require iterative algorithms to solve them. One of those algorithms is the Sturmian root solver. The following list shows all objects for which the Sturmian root solver can be used.
Textures are combinations of pigments, normals, finishes and halos.
Pigment is the color or pattern of colors inherent in the material. Normal is a method of simulating various patterns of bumps, dents, ripples or waves by modifying the surface normal vector. Finish describes the reflective and refractive properties of a material. Halo simulates effects like clouds, fog, fire etc. A plain texture consists of a single pigment, an optional normal, a single finish and optionally one or more halos.