We present a new 3D lens rendering technique and a new spatiotemporal lens. Interactive 3D lenses, often called volumetric lenses, provide users with alternative views of data sets within 3D lens boundaries while maintaining the surrounding overview (context). In contrast to previous multipass rendering work, we discuss the strengths, limitations, and performance costs of a single-pass technique especially suited to fragment-level lens effects, such as color mapping, lighting, and clipping. Some object-level effects, such as a data set selection lens, are also incorporated, with each object's geometry being processed once by the graphics pipeline. For a substantial range of effects, our approach supports several composable lenses at interactive frame rates without performance loss during increasing lens intersections or manipulation by a user. Other cases, for which this performance cannot be achieved, are also discussed. We illustrate possible applications of our lens system, including Time Warp lenses for exploring time-varying data sets.

This paper extends 3D lens techniques. Interactive 3D lenses, often called volumetric lenses, provide users with alternative views of datasets within spatially bounded regions of interest (focus) while maintaining the surrounding overview (context). In contrast to previous multi-pass rendering work, we discuss the strengths, limitations, and performance cost of a single-pass technique. For a substantial range of effects, it supports several interactive composable lenses at interactive frame rates without performance loss during increasing lens intersections or manipulations. Other cases, for which this performance cannot be achieved, are also discussed. Finally, we illustrate possible applications of our lens system, especially new Time Warp lenses for exploring time-varying datasets in interactive VR.

We present and evaluate a new approach for real-time rendering of composable 3D lenses for polygonal scenes. Such lenses, usually called "volumetric lenses," are an extension of 2D Magic Lenses to 3D volumes in which effects are applied to scene elements. Although the composition of 2D lenses is well known, 3D composition was long considered infeasible due to both geometric and semantic complexity. Nonetheless, for a scene with multiple interactive 3D lenses, the problem of intersecting lenses must be considered. Intersecting 3D lenses in meaningful ways supports new interfaces such as hierarchical 3D windows, 3D lenses for managing and composing visualization options, or interactive shader development by direct manipulation of lenses providing component effects. Our 3D volumetric lens approach differs from other approaches and is one of the first to address efficient composition of multiple lenses. It is well-suited to head-tracked VR environments because it requires no view-dependent generation of major data structures, allowing caching and reuse of full or partial results. A Composite Shader Factory module composes shader programs for rendering composite visual styles and geometry of intersection regions. Geometry is handled by Boolean combinations of region tests in fragment shaders, which allows both convex and nonconvex CSG volumes for lens shape. Efficiency is further addressed by a Region Analyzer module and by broad-phase culling. Finally, we consider the handling of order effects for composed 3D lenses.

Our work describes the simulation of a planar network of spiking I/F neurons on graphics processing hardware. The described approach adds to the fast-growing field of general-purpose computation on GPUs (GPGPU). We provide an in-depth explanation of the steps involved in implementing the network using programmable shading hardware. We replicated simulation results by Hopfield et al. and Maida et al. and give qualitative and quantitative measures of our implementation.

We demonstrate composable volumetric lenses as interpretational tools for geological visualization. The lenses provide a constrained focus region that provides alternative views of datasets to the user while maintaining the context of surrounding features. Our rendering method is based on run-time composition of GPU shader programs that implement per-fragment clipping to lens boundaries and surface shader evaluation. It supports composition of lenses and the user can influence the resulting visualization by interactively changing the order in which the individual lens effects are applied. Multiple shader effects have been created and used for interpretation of high-resolution elevation datasets (like LTDAR and SRTM) in our lab.