SymmSketch: creating symmetric 3D free-form shapes from 2D sketches

Abstract

This paper presents SymmSketch — a system for creating symmetric 3D free-form shapes from 2D sketches. The reconstruction task usually separates a 3D symmetric shape into two types of shape components, that is, the self-symmetric shape component and the mutual-symmetric shape components. Each type of them can be created in an intuitive manner. According to a uniform symmetry plane, the user first draws 2D sketch lines for each shape component on a sketching plane. The z- depth information of the hand-drawn input sketches can be calculated using their property of mirror symmetry to generate 3D constructive curves. In order to provide more freedom for controlling the local geometric features of the reconstructed free- form shapes (such as their cross sections will not be limited to be traditional circular), our modeling system will create each shape component from four constructive curves. With one pair of symmetric curves and one pair of general curves, an improved cross-sectional surface blending scheme is applied to generate a parametric surface for each component. The final symmetric free- form shape will be progressively created and be represented as 3D triangular mesh. Experimental results illustrate that our system can generate symmetric complex free-form shapes effectively and conveniently.