Image-Swept Volumes

Many graphical objects can be represented by swept volumes (including its subset — generalised cylinders) by sweeping 2D or 3D templates along 3D trajectories. In this paper, we present a new approach for constructing swept volumes using image templates. We utilise scalar fields as our underlying data type, and employ volume ray casting techniques for rendering swept volumes in their original sweeping specifications as well as in their voxelised approximations. In addition to some simple image‐swept volumes, we also treat multi‐channel image templates, video templates, generalised sweeps, and self‐intersecting trajectories. This approach enables us to model swept volumes with heterogeneous interiors and amorphous effects. It also facilitates the use of constructive volume geometry for creating complex scenes in both modelling and rendering space.     

Partitioned Shadow Volumes

Real‐time shadows remain a challenging problem in computer graphics. In this context, shadow algorithms generally rely either on shadow mapping or shadow volumes. This paper rediscovers an old class of algorithms that build a binary space partition over the shadow volumes. For almost 20 years, such methods have received little attention as they have been considered lacking of both robustness and efficiency. We show that these issues can be overcome, leading to a simple and robust shadow algorithm. Hence we demonstrate that this kind of approach can reach a high level of performance. Our algorithm uses a new partitioning strategy which avoids any polygon clipping. It relies on a Ternary Object Partitioning tree, a new data structure used to find if an image point is shadowed. Our method works on a triangle soup and its memory footprint is fixed. Our experiments show that it is efficient and robust, including for finely tessellated models.     

Display of Density Volumes

The advent of inexpensive, high-speed processing and storage has fueled interest in new ways to process and display 3D images. This new discipline of 3D imaging promises to produce a wealth of exciting applications in many fields. For three years, engineers at Linkoping University have experimented with algorithms and methods to display 3D images obtained from a variety of sources, including computer-aided tomography, transmission electron microscopy, and laser microscopy. This article reviews the applicability of different display methods for different types of volumes, the advantages and disadvantages of different techniques, and the results of experiments when image processing techniques were applied before the images were displayed.     

Volumes 15 and 16

Authors Index

Volumes 15 and 16