This paper presents a new three-dimensional display system using a reconfigurable projection manifold. The display surface is warped interactively into a non-planar manifold according to the scene image's depth information for the current view. Scene images are projected onto the display using computer graphics and a post-process warping. We currently use two projections to provide a complete coverage of the manifold surface from oblique projection angles. In this paper, we describe the overall design issues and goals of the projector-based rendering process, introduce the algorithms to model the projection manifold surface and describe the algorithms used to create the pre-warped images from the scene image. Our current prototype is a discrete tile-based approximation to the depth manifold. We describe our experiments with two such prototypes, one using a static test configuration, and another actuated using linear motion controllers for each discrete tile. This second prototype can be configured dynamically, as the depth information in the scene changes.

Some applications require scenes mixing polygonal and volumetric objects and shadows make the scenes more realistic. This paper describes a shadow algorithm for mixed polygonal and volumetric data, including the generation of soft shadows for area light sources. Our volume shader leverages advanced graphics GPU for an accelerated and feasible solution. The shadow and soft shadow algorithm applies to all combinations of volumes and polygons, without any restriction on the geometric positioning and overlap of the volumes and polygons. For realistic rendering where we have a high albedo participating media, multiple scattering is significant. We extend our algorithm to handle both multiple forward scattering and back scattering with light attenuation. This constitutes a complete system for shadow generation and light propagation.

Traditional flow volumes construct an explicit geometrical or parametrical representation from the vector field. The geometry is updated interactively and then rendered using an unstructured volume rendering technique. Unless a detailed refinement of the flow volume is specified for the interior, information inside the underlying flow volume is lost in the linear interpolation. These disadvantages can be avoided and/or alleviated using an implicit flow model. An implicit flow is a scalar field constructed such that any point in the field is associated with a termination surface using an advection operator on the flow. We present two techniques, a slice-based three-dimensional texture mapping and an interval volume segmentation coupled with a tetrahedron projection-based renderer, to render implicit stream flows. In the first method, the implicit flow representation is loaded as a 3D texture and manipulated using a dynamic texture operation that allows the flow to be investigated interactively. In our second method, a geometric flow volume is extracted from the implicit flow using a high dimensional isocontouring or interval volume routine. This provides a very detailed flow volume or set of flow volumes that can easily change topology, while retaining accurate characteristics within the flow volume. The advantages and disadvantages of these two techniques are compared with traditional explicit flow volumes.

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