RenderPark User Guide

What is RenderPark?

RenderPark is a photo-realistic rendering program. You feed it with a 3D model (geometry and material properties). RenderPark then computes either a photo-realistically illuminated 3D model or a high- or low-dynamic range image of the model as seen from a particular view.

RenderPark is different than other renderers in that it uses a physically-based illumination simulation in order to do its job. Because of its physically-based approach, the resulting illuminated model and the images computed with RenderPark will (ideally) be as close as to reality as the input allows. RenderPark is suited for quantitative prediction of the illumination in buildings that have not yet been built for instance. In order to achieve this goal, RenderPark needs physically-based material descriptions of the surfaces in a scene. A light source will be described by its luminous power for instance rather than just a color.

In the remainder of this user guide, we assume that you are familiar with global illumination (radiosity, ray-tracing). Good introductions to global illumination can be found in:
- M. Cohen and J. Wallace, "Radiosity and Realistic Image Synthesis", Academic Press Professional, 1993
- F. Sillion and C. Puech, "Radiosity and Global Illumination", Morgan Kaufman, 1994
- P. Shirley, "Realistic Ray Tracing", A. K. Peters, 2000
- Various ACM SIGGRAPH courses



RenderPark Screen Shot: Choosing a Radiance Method

1. Loading a 3D model

Load a scene by selecting the 'Load Scene' button in the File menu. RenderPark reads files in the Materials and Geometry Format (MGF). A small collection of scenes is provided in the SCENES subdirectory. More scenes are available on the web site.

2. Radiosity

Select a radiosity (or better: world-space radiance) method in the Radiance menu (see screenshot above). You can set control options after pressing the 'Control' button. You start/interrupt the computations using the Run/Stop button. Currently available world-space radiance methods are:

3. Rendering and saving the illuminated model

You can control the way the illuminated model after radiosity is rendered using graphics hardware with the options in the Rendering menu.
The resulting image can be saved using the 'Save image' button in the File menu. RenderPark supports the PPM and TIFF image file formats. Numerous convertors and image manipulation tools exist for these formats.
You can also save the illuminated 3D model after a radiosity computation in VRML'97 format using 'Save Model' in the file menu. .

4. Ray-tracing

After a world-space radiance computation (if you did one), a per-pixel (ray tracing) pass can be used to make a very precise image using the current virtual camera. Choose a ray-tracing method by selecting the 'Method' button in the 'RayTracing' menu. You can choose between You can control parameters in the panel you get after clicking the 'Control' button. Start/Stop the computations by selecting the Run/Stop button. The resulting image can be saved using the 'Save Image' button. In addition to PPM and "normal" TIFF format, you can also save in in high dynamic range (logluv) TIFF format by specifying .logluv as the file name extension here. The most recently computed image can be redisplayed at any time by clicking the 'Redisplay' button'.

5. Interactive navigation

When the program is not busy rendering (indicated with a spray can cursor), you can manipulate the virtual camera by moving the mouse on the canvas window while pressing a button. By default (3-button motion), you You can also edit, save and restore the virtual camera manually in the 'Camera' menu.

6. The photon map

RenderPark now contains a rendering technique called the Photon Map: The photon map is a two-pass method for computing very high quality images of models exhibiting general illumination. It is faster than bi-directional path tracing at the cost of some approximations.

It is a two-pass method:

7. Tone mapping

All rendering algorithms in RenderPark require that radiometric intensities be mapped to display colors at the end. The process of mapping radiometric intensity values to display colors is called tone mapping. The 'Tone Mapping' menu offers a variety of tone mapping strategies, allows to brighten or darken images artificially and lets you take advantage of a calibrated monitor.

8. Batch rendering

RenderPark accepts numerous command line options. It can be used for batch rendering as well as for rendering into an external canvas window. It can also be controlled using Inter Process Communication. Type 'rpk -help' to see what options are available.

Page maintained by the RenderPark web team
Last update: October 31, 2000