Thomas V. Thompson

Direct haptic rendering of sculptured models

A new tracing algorithm is described that supports haptic rendering of NURBS surfaces without the use of any intermediate representation. By using this tracing algorithm in conjunction with algorithms for surface proximity testing and surface transitions, a complete haptic rendering system for sculptured models has been developed. The system links an advanced CAD modeling system with a Sarcos force-reflecting exo-skeleton arm. A method for measuring the quality of the tracking component of the haptic rendering separately from the haptic device and force computation is also described. CR Descriptors: H.1.2 [Models and Principles] User/Machine Systems; C.3 [Special-Purpose and Application-Based Systems] Real-Time Systems; I.3.7 [Computer Graphics] Three-Dimensional Graphics and Realism; I.6.4 [Simulation and Modeling] Types of Simulation - Distributed; F.2.2 [Analysis of Algorithms and Problem Complexity] Nonnumerical Algorithms and Problems; J.6 [Computer-Aided Engineering].

Painting textures with a haptic interface

We present a method for painting texture maps directly onto trimmed NURBS models using a haptic interface. The haptic interface enables an artist to use a natural painting style while creating a texture. It avoids the traditional difficulty of mapping between the 2D texture space and the 3D model space by using parametric information available from our haptic tracing algorithm. The system maps user movement in 3D to movement in the 2D texture space and adaptively resizes the paintbrush in texture space to create a uniform stroke on the model.

Direct haptic rendering of complex trimmed NURBS models

The most accurate haptic rendition of a virtual model is produced when the haptic algorithm acts directly on the actual model and not an intermediate representation. In the modeling and design communities the de facto model representation standard is NURBS. Further, more powerful systems provide trimming and adjacency information within the models representation. This additional information permits more complex models to be expressed succinctly but also increases the complexity of representation. In this paper we present an algorithm that supports direct haptic rendering of models constructed from trimmed NURBS surfaces. Our distributed system links an advanced modeling system to a force-reflecting device. In addition, we present extensions to the algorithm which support model manipulation, dimensioned probes, and multi-probe contact.

XGen: arbitrary primitive generator

The visual richness of a CG movie comes in large part from the complexity of its characters and backgrounds. The high grass of Shrek, the trees of Ice Age, and the fur of Monsters Inc. are all examples of this. While each of these poses its own unique challenges, they all have one thing in common: they involve populating primitives (grass, leaves, fur) across large pieces of geometry (ground, tree, monster) in a controllable manner.

Brain freeze

Sections: (based on January rating supplement)  2 Non-rated: Grades K-3, 4-6. Games not rated, notation not required, clocks not required but used if both players agree. Players with 10 or more rated games, or 25 or more prior tournament games (including non-rated), are not eligible. May enter one section higher if needed to stay with team.  Rated: (including unrated and provisionally rated players) U600 (K-12), U900 (K-12), Open (K-12). USCF membership required. Bring clocks! Notation optional for grade K-3 players in U600/U900 but may lose the right to make claims requiring a score sheet; required for all others.

Dragon scales: the evolution of scale tool for Reign of Fire

In recent years there have been several movies starring creatures with scaled surfaces. Among these are Jurassic Park, Dragonheart, and Lake Placid. The surfaces of these creatures have generally been constructed by layering painted textures atop displacement maps. This gives the model texture, but the scales stretch and shrink under the movement of the creature, giving a rubbery look that is not realistic.