We present a powerful framework for 3D-texture-based rendering of multiple arbitrarily intersecting volumetric datasets. Each volume is represented by a multi-resolution octree-based structure and we use out-of-core techniques to support extremely large volumes. Users define a set of convex polyhedral volume lenses, which may be associated with one or more volumetric datasets. The volumes or the lenses can be interactively moved around while the region inside each lens is rendered using interactively defined multi-volume shaders. Our rendering pipeline splits each lens into multiple convex regions such that each region is homogenous and contains a fixed number of volumes. Each such region is further split by the brick boundaries of the associated octree representations. The resulting puzzle of lens fragments is sorted in front-to-back or back-to-front order using a combination of a view-dependent octree traversal and a GPU-based depth peeling technique. Our current implementation uses slice-based volume rendering and allows interactive roaming through multiple intersecting multi-gigabyte volumes.

We have developed a new input device that allows users to intuitively specify three-dimensional coordinates in graphics applications. The device consists of a cube-shaped box with three perpendicular rods passing through the center and buttons on the top for additional control. The rods represent the X, Y, and Z axes of a given coordinate system. Pushing and pulling the rods specifies constrained motion along the corresponding axes. Embedded within the device is a six degree of freedom tracking sensor, which allows the rods to be continually aligned with a coordinate system located in a virtual world. We have integrated the device into two visualization prototypes for crash engineers and geologists from oil and gas companies. In these systems the Cubic Mouse controls the position and orientation of a virtual model and the rods move three orthogonal cutting or slicing planes through the model. We have evaluated the device with experts from these domains, who were enthusiastic about its ease of use.

This paper describes tools and techniques for the exploration of gee-scientific data from the oil and gas domain in stereoscopic virtual environments. The two main sources of data in the exploration task are seismic volumes and multivariate well logs of physical properties down a bore hole. We have developed a props-based interaction device called the cubic mouse to allow more direct and intuitive interaction with a cubic seismic volume. This device effectively places the seismic cube in the user's hand. Geologists who have tried this device have been enthusiastic about the ease of use, and were adept only a few moments after picking it up. We have also developed a multi-modal, visualisation and sonification technique for the dense, multivariate well log data. The visualisation can show two well log variables mapped along the well geometry in a bivariate colour scheme, and another variable on a sliding lens. A sonification probe is attached to the lens so that other variables can be heard. The sonification is based on a Geiger-counter metaphor that is widely understood and which makes it easy to explain. The data is sonified at higher or lower resolutions depending on the speed of the lens. Sweeps can be made at slower rates and over smaller intervals to home in on peaks, boundaries or other features in the full resolution data set.