Animations Bio Home Images Links Publications

Ray Tracing

Ray tracing is probably the best known technique for rendering photorealistic images. Ray tracing is particularly good at simulating sharp shadows, mirrors and glass while other effects such as caustics and colour bleeding are neglected. An advantage of ray tracing based rendering approaches compared to radiosity is that they handle procedural models and complex objects that do not need tessellation.

See the Cornell box images for a comparison between ray tracing and global illumination. See my book to find out how to add global illumination and caustics to a ray tracer :)

The Sphereflake

The sphereflake was introduced (I believe) by Eric Haines in his database SPD for testing the speed of ray tracing software. This particular sphereflake is one my early ray traced images (1992). It is a procedural (fractal object). Here approximated using 500.000 spheres. Even though it is old I still like it :)

A dragon made of frosted glass

This is a rendering of the dragon model using a microfacet model for refraction. I derived this model with Josh Wills in the fall of 2003 only to find out that Jos Stam had derived it earlier in his 2001 EGSR paper. Oh well...

A ray traced 4D Julia fractal

This is a 3D ray traced rendering of a 4D Julia fractal (evaluated as the standard 2D version except this one uses 4D quaternions).

A Fractal Egg

This fractal egg is an example of a hypertexture as introduced by Perlin and Hoffert in 1989. The egg is a simple implicit surface defining a density in world space. By subtracting a turbulence function from this density we get a fractal egg.

A Fireball

The fireball is another example of a hypertexture. Here the implicitly defined sphere specifies density as well as emission. Both of these are changed using a modified turbulence function.

Sweeping a sphere through space

This model was created by sweeping a sphere through space along the trajectory of a spline. 8 spheres with different radi placed at the corners of a cube were used to construct the spline curve.

Sweeping a sphere through space

One of my first ray tracing images (1990-1991). Rendered first time on an Amiga in HAM mode (the good old days).

A glossy Steinbach Screw

The Steinbach Screw reflected into a glossy mirror.

Another Steinbach Screw

The Steinbach Screw is a mathematical function sampled using coloured spheres.

A Tetraoid

The Tetraoid.

The ancient village of Lejre

This is a model of lejre (an ancient Danish viking village) created in AutoCAD by Flemming Vestergaard and Hans Peter Nielsen. The model is made of 29000 triangles. Each tree is made of 10 triangles which of course significantly limits the obtained realism.

Last update: May, 2007