3D models are widely used in diverse fields such as movie, animation and graphics industry. General 3D modeling work is complicated, tedious and time-consuming. To make the 3D modeling process simple, several sketching interfaces were proposed. In this thesis, we present an interactive 3D modeling system based on a sketching interface. Once a user draws a contour on 2D plane, our method creates a 3D model of which silhouette fits the contour drawn by the user.
Our modeling system consists of four steps : the skeleton extraction, the metaball placement, the computation of metaballs' radii and the mesh construction. l)We extract a skeleton from the user-drawn contour. 2)We create an implicit surface by placing metaballs on the skeleton. If the distance between consecutive metaballs is too far, the surface may become unnecessarily bumpy. We compute the maximum distance between two consecutive metaballs whose surface is not bumpy. 3)Radii of metaballs is computed to fit the surface to the user-drawn contour. We propose a modification of the metaball equation; this modification allows us to reduce the computation time of the fitting process. 4)Finally, a modified marching cube method is proposed for visualizing the implicit surface. Consequently, users become easily familiar to our system because this system react immediately to user's editing.
