Physics Based
Modeling & Simulation

Real-Time Terrain Rendering

Real-Time Volume Rendering

The following video depicts operation of a volume rendering software tool developed for a small atmospheric research company. The windows based tool uses DirectX and optimizations based on detected video hardware. It is customized to read and filter Weather Research and Forecasting (WRF) datasets for viewing such parameters as Temperature, Water Vapor, Pressure and Relative Humidity in a 3D volume. During real-time viewing, the complete dataset can be filtered with "slider bars" to set the min and max data clipping values, and can also be instantaneously mapped to linear, logarithmic and exponential functions to readily analyze/enhance specific features.

Physics-Based Multiple Scattering

The following videos demonstrate a tool developed completely by waveI staff for a USAF SBIR contract to visualize physically realistic gaseous phenonmenona. The cloud volume is described solely by cells of Liquid Water Content (LWC) and droplet size distributions. All cloud multiple scattering computations use Mie theory for 3 visible bands of light. The sky is modeled as approximately 20 scattering layers and uses a dry atmosphere Rayleigh model to attenuate light reaching the cloud volume and also directly scattered to the image plane. The first video depicts a fixed low horizon sun location while the camera orbits a synthesized cloud volume. Mie effects are immediately evident from 1st and 2nd order scattering effects in the forward and back scattered directions. The ambient lighting of the volume from ground and sky components is approximated with a diffusion model. The Glory and Fogbow effect are readily demonstrated with the Mie model. The next video uses an identical synthesized cloud volume as above, but demonstrates cloud and sky solar light scattering for the sun at differential azimuths between high noon and sunset. The orange cloud hue at sunset is purely due to attenuation of the blue bands through Rayleigh scattering through the much thicker atmosphere traversed along the horizon.

Historical Development

Real-Time Terrain Renderer

In the mid 1990s, waveI key members developed the first real-time terrain renderer that read raw DTED data and rendered directly to screen without pre-processing for polygon generation. We made use of the MeshSP, a "Desktop Supercomputer" developed at MIT Lincoln Labs. The MeshSP has 64 Analog SHARC processors (ADSP61062) connected in a nearest neighbor grid + 2 extra communication paths per chip. (That 7.7 GFlops platform cost $100,000 in 1996!!! Would you care to buy it?)

waveI members also demonstrated the first raytracing algorithms to be implemented on the MeshSP architecture. This image depicts a buckyball configuration of 60 reflecting spheres surrounding a single reflecting sphere. Real-time demonstrations were shown at SIGGRAPH.

Real-Time Volume Renderer

Direct X Implementation

Physics-Based Multiple Scattering

Custom Renderer Using Mie Scattering