Research On Sketch-based 3D Modeling

Sketch is an effective, natural way to interact. In design, sketch is an indispensable tool for product innovation and of great value in conceptual design phase. Sketches based on the traditional pen and paper cannot directly interact with computer, this shortcoming is particularly evident in the field of computer modeling. The traditional CAD tools are designed for the detailed modeling phase, which cannot meet the requirements for earlier conceptual design. There is an urgent need for a method that combines advantages of sketch and CAD modeling. This paper’s work is focused on the establishment of a new modeling technique based on hand-drawn sketches with gesture-based human-computer interaction, it meets the needs of the user’s modeling on the conceptual design phase. This paper’s work combines the advantages of natural sketches and computer modeling, it upgrades user’s creativity of production. Accordingly, we research on the key technologies involved and a prototype of sketch-based 3D modeling system is developed. The main content of our research is as follows:(1) The sketch processing techniques and semantic understanding framework are given and 2D sketch pre-processing, gesture design, sketch discipline are researched. The details of sketch semantic understanding was discussed which makes gesture command and sketch 3D modeling integrated into one interaction interface.(2) A HMM-based gesture recognition method is proposed with two optimized methods: midpoint compensation and improved feature coding. The experiment shows our recognition model gives good recognition result. Based on that a relative feedback is introduced to enhance the recognition precision.(3) A comprehensive 3D modeling method combines one stroke modeling and two stroke modeling is presented, which can support solid modeling, inflation modeling and surface modeling. It is compatible with different users, gesture styles. It greatly expands the use’s expression’s way and range.(4) The design and implementation of a sketch-based 3D modeling prototype system are accomplished. The system’s architecture, class diagram and model examples are given, which verify this paper’s research work.