Quotes from the SIGGRAPH'96 Course No.11
Implicit Surfaces for Geometric Modeling and Computer Graphics
co-chaired by Jai Menon and Brian Wyvill

“Three major lines of work in implicit models:

• algebraic surfaces;
• blobby objects;
• functional representations.”

“F-rep is an attempt to step to a more general modeling scheme using real functions.”

Download the first part of the SIGGRAPH'96 course No.11 (1.2 Mb PostScript zipped file) including
An Introduction to Implicit Techniques by J.Menon.