Technical illustration based on human-like approach

In this paper, we present a human-like non-photorealistic rendering approach. A typical process of how human engineers learn to paint technical illustration is as follows: At first they are trained on how to paint separate primitives such as cubes and spheres, and accordingly accumulate the empirical drawing principles and skills during their continuous practices, and finally they can freely express complicated shapes and engineering information in their illustrations by composing the related primitives' drawings. We manage to mimic this human-like approach by embedding established illustration rules into primitives' lighting models and its drawing algorithms, and implement it in an illustration system-RETOUCH.