Implicit surface visualisation using Adaptive Raymarching

Indirect methods for visualisation of implicit surfaces use triangulated mesh for object shape aproximation. The overall visualisation quality thus depends on the degree of surface tessalation. Direct visualization approach by Raytracing based methods requires computation of an object-ray intersection point which is problematic and computationally expensive. The article discusses Adaptive Raymarching as an implicit surface realtime visualisation method which uses distance functions for object modeling. The knowledge of distance to the closest surface based on distance functions at each spatial point in the scene allows us to adaptively optimize ray marching distance to the maximal possible length each step, thus lowers amout of calculation steps for the object-ray intersection evaluation. Disadvantages of the aformentioned approach such as a rapid increase of ray steps along surface edges are discussed in the article. Function descriptions for distance estimation of basic quadrics are presented along with an advanced shading algorithm including ambient occlusion estimation an