Interactive Distributed Ray-Tracing of Highly Complex Models

Ingo Wald, Philipp Slusallek, and Carsten Benthin 
in Rendering Techniques 2001 / Proceedings of the EUROGRAPHICS  Workshop on Rendering 2001, pp 274 -285, London, June 2001 

[bib] [pdf]


Many disciplines must handle the creation, visualization, and manip-ulation of huge and complex 3D environments. Examples include large structural and mechanical engineering projects dealing with entire cars, ships, buildings, and processing plants. The complexity of such models is usually far beyond the interactive rendering capabilities of todays 3D graphics hardware. Previous ap-proaches relied on costly preprocessing for reducing the number of polygons that need to be rendered per frame but suffered from excessive precomputation times often several days or even weeks. 
In this paper we show that using a highly optimized software ray tracer we are able to achieve interactive rendering performance for models up to 50 million triangles including reflection and shadow computations. The necessary prepro-cessing has been greatly simplified and accelerated by more than two orders of magnitude. Interactivity is achieved with a novel approach to distributed render-ing based on coherent ray tracing. A single copy of the scene database is used together with caching of BSP voxels in the ray tracing clients.

Paper Gallery

This page contains still images and movies created during this project

The PowerPlant Model has been provided by Anselmo Lastra from UNC. It shows a fully modelled power plant and consists of roughly 12.5 million triangles. With our interactive distributed ray tracing system, we have been able to render the whole (i.e. non-simplified) model at interactive frame rates. In total, only seven dual-PentiumIII linux boxes have been used to create the following animations.

All animations have been rendered WITHOUT ISSE support. Since ISSE support is now turned on again, the achieved framerate is about twice as high in the newest version of the system. 

Still Images


Click for the images to see the full-resolution images (640x480) as they have been 'live' captured from the running system. Seven dual-PentiumIII (800-866 MHz) linux boxes have been sufficient to achieve the frame rates as shown in the title bars of the screenshots.


Some outside views:

With reflections and Lightting:

The right image shows even the entire powerplant reflected in one of the tubes. 

Some inside views:


Due to compression, resampling and rescaling, all movies are quite blurry. The original rendering quality can be seen in the still images below. Also note that the 'jaggy' camera movement results from the user interface, not from lacking rendering speed.

All animations are rendered in 640x480 pixels if not stated otherwise.

  • "The Powerplant"
    [avi, 29Mb]
    an animation showing a camera path that goes from the outside to the inside of the powerplant
  • "FlyAround
    [avi, 37Mb] 
    an animation that shows a camera flight around the powerplant
  • "The Furnace"
    [avi, 13.5Mb]
    an animation showing the geometric complexity of the powerplants furnace
  • "Shadows and Reflections
    [avi, 7.5Mb]
    image resolution: 320x240
    the powerplant with raytraced shadows and reflections