chiaroscuro

An illumination renderer for 3D models.

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usage
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technical info
work in progress

Chiaroscuro is a raytracer for illuminating 3D models. Unlike conventional raytracers that render 2D images, chiaroscuro calculates illumination values for each polygon and vertex. Therefore, chiaroscuro is particularly suitable to provide smooth and realistic shading for realtime architectural walkthrough models.

Screenshots.

simple example scene provided in the packages

Usage. The binary packages of chiaroscuro contain three executable. The usage of the interactive graphical main application chiaroscuro is explained in more detail in the tutorial. The other two executables elmofire and elmoshift are command line tools that offer the same functionality from a standard console/DOS window. Therefore, they lend themselves well to automatically render and post-process multiple scenes via shell scripts or batch files. Type elmofire -h and elmoshift -h to get a brief overview on available command line switches.

Download. Chiaroscuro is available as precompiled binaries for Windows and Linux as well as in source code form. If you want to compile chiaroscuro yourself, please have a look at the technical info section in order to solve its external dependencies.

chiaroscuro_0_9.tar.gz - binary for Linux
chiaroscuro_0_9.zip - binary for Windows
chiaroscuro_0_9_source.zip - source code for all platforms

Technical info. Chiaroscuro has been designed and implemented by Gerald Franz. The latest version and the source code is available at the original chiaroscuro website.
The application makes use of the veLib for loading and displaying the 3D models. The user interface is made using the FLTK toolkit (version >= 1.1.5). The veLib texture loaders internally use libPNG and zlib for PNG display and are based in part on the work of the Independent JPEG Group.
Chiaroscuro is provided under the terms of the GNU General Public License.

Work in progress. Chiaroscuro has reached a first fully productive and fairly stable state. Nevertheless, diffuse 3D scene illumination is a complex issue, therefore the development of the application will definitively continue. Depending on the actual demands, future releases will likely offer the following features:

Complete undo functionality also affecting luminary operations.
A more physics-oriented illumination model internally using realworld luminance values and considering the area of faces.
Various performance improvements. The scene geometry for ray tracing will be likely organized as an octree. Furthermore, future versions will take advantage of multiple CPU cores by parallelizing the ray tracing process in multiple threads, either per vertex or per mesh.
Multiple rendering passes. Analogous to radiosity renderers, vertex illumination values obtained by the rendering may be used as luminaries for further passes.
Colored lights. The colors of the vertices of the luminary files may be taken into account.
Realistic skylight illumination based on algorithms described by Preetham et al..

2006-04-23