Implicit representation of molecular surfaces

Molecular surfaces are an established tool to analyze and to study the evolution and interaction of molecules. One of the most advanced representations of molecular surfaces is called the solvent excluded surface. We present a novel and a simple method for representing the solvent excluded surfaces (SES). Our method requires no precomputation and therefore allows us to vary SES parameters outright. We utilize the theory of implicit surfaces and their CSG operations to compose the implicit function representing the molecular surface locally. This function returns a minimal distance to the SES representation. Additionally, negative values of the implicit function determine that the point lies outside SES whereas positive ones that the point lies inside. We describe how to build this implicit function composed of three types of patches constituting the SES representation. Finally, we propose a method to visualize the iso-surface of the implicit function by means of ray-casting and the set of rendering parameters affecting the overall performance.