> Though I've never actually seen anybody implement Loop-Blinn for cubics I implemented them (implicit formulation of rational cubic bezier curves) in my rende

> Though I've never actually seen anybody implement Loop-Blinn for cubics I implemented them (implicit formulation of rational cubic bezier curves) in my renderer (see one of my other replies in this thread). Here is an extract of the relevant code in a shader toy: https://www.shadertoy.com/view/WlcBRn https://www.shadertoy.com/view/WlcBRn Even in Jim Blinn's book "Notation, Notation, Notation" he leaves some of the crucial equations as an exercise to the reader. I remember spending 2 or 3 weeks reading and trying to understand everything he wrote to derive these equations he hinted at myself.