Sketch-Based 3D Free-Form Modeling

This article presents a 3D modeling approach that uses the varational implicit surface as a geometric representation for free-form shapes.The modeling processes are described in detail and the problems that deserve special attention in each step are pointed out.A robust program for sketching free-form silhouette is designed.Program running tests show that the varational implicit surface modeling is smooth and closed,and convenient for fusion and other follow-up operations.