Sketching 3D Shapes with Variational Implicit Surfaces
We have developed a system that allows the creation of certain freeform objects with a sketching interface. "Sketching" means gestural marks in 2D to model shapes. We have observed that a particular representation for underlying geometry - the variational implicit surfaces - allow a unified method for a collection of free-from modeling operations. In this work, we have created operations for easy editing of shapes and developed techniques based on variational implicit surfaces. With the ability to convert the models to and from the traditional polygonal format, the underlying representation remains transparent to the user. The techniques are ideal for creating smooth free-from shapes.
Background & Objective: With the advent of sketch-based methods for shape construction, there’s a new degree of power available in the rapid creation of approximate shapes. Just as in children’s sketching books, one is taught to first draw the general forms of things starting from simple pieces (cylinders, spheres, cones, blobs etc ), and then to draw a more careful outline and erase the underlying shapes, we provide the user the opportunity to roughly sketch out shapes and then modify them to provide a final form.
Technical Discussion: We provide three basic operations: (i) "inflate" 2D stroke into a 3D shape (ii) "merge" two or more 3D objects into a single object with a guidance stroke and (iii) "modify" by oversketching an existing shape. Â Â The basic idea is to simply remove or add constraints on an implicit surface to create, merge or modify the shapes. The constraints are inferred from user-supplied strokes. In addition, we use an automatic hierarchy generation method to represent the parent-child relationship between objects as they are created.
Publications:
Technology Areas:
Graphics
Off the Desktop Interaction and Display
Modification Date: July 7, 2008