Alan Sullivan

High accuracy NC milling simulation using composite adaptively sampled distance fields

We describe a new approach to shape representation called a composite adaptively sampled distance field (composite ADF) and describe its application to NC milling simulation. In a composite ADF each shape is represented by an analytic or procedural signed Euclidean distance field and the milled workpiece is given as the Boolean difference between distance fields representing the original workpiece volume and distance fields representing the volumes of the milling tool swept along the prescribed milling path. The computation of distance field of the swept volume of a milling tool is handled by an inverted trajectory approach where the problem is solved in tool coordinate frame instead of a world coordinate frame. An octree bounding volume hierarchy is used to sample the distance functions and provides spatial localization of geometric operations thereby dramatically increasing the speed of the system. The new method enables very fast simulation, especially of free-form surfaces, with accuracy better than 1 micron, and low memory requirements. We describe an implementation of 3 and 5-axis milling simulation.

Intermediate view generation for perceived depth adjustment of stereo video

There is significant industry activity on delivery of 3D video to the home. It is expected that 3D capable devices will be able to provide consumers with the ability to adjust the depth perceived for stereo content. This paper provides an overview of related techniques and evaluates the effectiveness of several approaches. Practical considerations are also discussed.

Electronic poster: parallel algorithms for high accuracy NC milling simulation

In the present work, we demonstrate multithreaded algorithms for high-accuracy NC milling simulation. Our approach to simulation - Boolean differences between a set of analytic or procedural, signed, Euclidiean distance fields - is able to represent a milled workpiece, produced from hundreds-of-thousands of milling instructions, in under 50MB of space to an accuracy of 1μm; however, computationally intensive ray-casting limits rendering and editing performance (ie, interactivity). To increase interactivity, we developed a master-workers thread-manager that could be integrated into the existing code-base with minimal changes. In our poster, we describe the details of our system, thread-manager, and approach to dividing the rendering/editing algorithms into units-of-work that are dispatched for execution by the thread-manager. Our experiments reveal performance gains near unity in the number of available cores (eg, 77-97% and >98% speedup per additional core for rendering and editing, respectively).