We describe star and nebula visualization techniques used to create a 3D volumetric visualization of the Orion Nebula. The nebula's ionization layer is modeled first as a surface model, derived from infrared and visible light observations. The surface model is imported into a volume scene graph‐based visualization system that uses procedural volume modeling to simulate the nebula's emissive gas layers. Additional scene graphs model proplyds and shock fronts within the nebula. Stars are rendered using Gaussian spots that are attenuated with distance. Finally, eighty‐six separate volumes are voxelized from these scene graphs, then simultaneously volume rendered.

Visualization techniques enable scientists to interactively explore 3D data sets, segmenting and cutting them to reveal inner structure. While powerful, these techniques suffer from one serious flaw-the images they create are displayed on a flat piece of glass or paper. It is not really 3D-it can only be made to appear 3D. We describe the construction of 3D physical models from volumetric data. Using solid freeform fabrication equipment, these models are built as separate interlocking pieces that express in physical form the segmentation and cutting operations common in display-based visualization.

Dramatic advances in 3D Web technologies have recently led to widespread development of virtual world Web browsers and 3D content.A natural question is whether 3D thumbnails can be used to find one's way about such 3D content the way that text and 2D thumbnail images are used to navigate 20 Web content We have conducted an empirical experiment that shows interactive 3D thumbnails, which we call worldlers, improve travelers' landmark knowledge and expedite wayfinding in virtual environments.

Virtual environment landmarks are essential in wayfinding: they anchor routes through a region and provide memorable destinations to return to later.Current virtual environment browsers provide user interface menus that characterize available travel destinations via landmark textual descriptions or thumbnail images.Such characterizations lack the depth cues and context needed to reliably recognize 3D landmarks.This paper introduces a new user interface affordance that captures a 3D representation of a virtual environment landmark into a 3D thumbnail, called a worldlet.Each worldlet is a miniature virtual world fragment that may be interactively viewed in 3D, enabling a traveler to gain first-person experience with a travel destination.In a pilot study conducted to compare textual, image, and worldlet landmark representations within a wayfinding task, worldlet use significantly reduced the overall travel time and distance traversed, virtually eliminating unnecessary backtracking.Landmarks are the subject of landmark knowledge, but also play a part in survey and procedural knowledge.In survey knowledge, landmarks provide regional anchors with which to calibrate distances and directions.In procedural knowledge, landmarks mark decision points along a route, helping in the recall of procedures to get to and from destinations of interest.Overall, landmarks help to structure an environment and provide directional cues to facilitate wayfinding. KEYWORDS: 3D thumbnails

Work in progress at the San Diego Supercomputer Center (SDSC) involving the implementation of network clients and servers to provide networkwide access to video devices is described. Applications anywhere on the net can manage record and playback operations, change video signal routing, or adjust scan converter parameters. Details of network communications, protocols, and device-specific control quirks are invisible to the user, making the video equipment a true network resource.>

An experimental volume visualization system, NetV, that distributes volume imaging tasks to appropriate network resources is described. NetV gives offsite scientists easy access to high-end volume imaging software and hardware. The system allows a user to submit volume imaging jobs to an imaging spooler on a visualization-server. Remote high-power compute engines process rendering tasks, while local workstations run the user-interface. The time required to submit a job, render the job on a mini-supercomputer-class machine, and return the volume imaging to the offsite scientist is far less than the time it would take to create a similar image on a local workstation-class machine.>

Software developed to deal with differing image file formats, mismatched byte order and word sizes, and confusing hardcopy device interfaces is described. The SDSC Image Tool suite provides a simple, extensible, and portable mechanism for the support of a variety of common image formats so that tool-writers can concentrate on the task in hand, rather than on the quirks of a particular image file format. Users of such tools are able to work with images generated from a variety of sources, without being restricted to an arbitrary standard format. The SDSC Visualization Printing suite creates a unified view of hardcopy devices.>