The ThingWorld modeling system: virtual sculpting by modal forces

Abstract

Vision and Modeling Group, E15-387, The Media Lab, M .I .T . 20 Ames St ., Cambridge MA 0213 8Abstrac tWe describe a real-time solid modeling system tha t is based on the physical analogy of forming cla y by applying forces . The system is implemented by simulating real materials as they react to usersupplied forces . Unlike other physically-based modeling approaches, the Thingworld system allows the user to restrict forming action to simple global deformations during the initial "roughing in" phase of modeling, and then later concer n themselves with detailing . The Thingworld syste m also allows users to automatically model existin g objects by using measurements taken from the object's surface . These measurements are used to generate artificial forces that mold the compute r model much as a human would mold a clay model . Timed examples for constructing solid models ar e shown .

Manipulating, Deforming and Animating Sampled Object Representations

“…For example, Hoppe et al [HDD*92] devised a reconstruction method based on determining the zero set of an estimated distance function. Distance fields were also used by Curless and Levoy [CL96] and Wheeler et al [WSI98] for reconstructing an implicit representation from point datasets. Lei et al [LBC96] fitted high degree implicit polynomials to point data.…”

“…The use of sculpting metaphor for surface‐based geometric modelling has been studied extensively (e.g., [Coq90, Nay90, SPE*90, SP86]). Galyean and Hughes [GH91] first introduced this concept to interactive volume modelling.…”

“…This class of models are designed to reduce the computational costs of above‐mentioned physically‐based models. For example, one may use a system of equations that are linearly independent [SPE*90], have a restricted class of deformation functions [WW90], use iterative solutions for the first‐order differential equation of deformation [BBC*94], preprocessing non‐linearity in high‐order differential models [CD99] and linear elasticity theory [MG04, KMH*04].…”