Interactive Ray Tracer

Ray Tracing defined

Ray Tracing is a very popular algorithm in computer graphics used for creating realistic pictures of scenes that have a defined 3D structure. A multitude of imaginary rays are sent from the viewer through the screen and into the 3D geometry. If a particular ray hits some object, the "imprint" of that object will appear on the screen at the place where the ray intersected it.

Using the Interactive Ray Tracer

24-bit color mode
First, make sure your monitor is in 24-bit color mode. The pictures will look really bad if you only have 8 bits of color (that is, 256 colors). You can usually adjust your color mode on PCs and Macs.

Gamma Correction
Second, set the appropriate gamma constant for your monitor by clicking on "gamma ??" and finding the right value. If you don't know your monitor's gamma, you can just "look it up" using Greg Ward's handy chart (see this or this for details).

Next, you are ready to set up your scene in the center window of the applet. As a default you are given a ground plane (really, a stretched out box) and one light (it's out of your field of view now). You can add boxes and lights and move them around with the mouse using radio buttons at the button of the applet. You can also stretch and squish the boxes and move your view point too. You can also set the color and surface for each box and also set color for each light. Use the select command to cycle through the objects.

Or you can just load a predefined scene by hitting the "DEMO" button. The is a sample output produced by my tracer for the DEMO:

Ray Tracing
Just hit the "TRACE" button and watch it go. The image will first be drawn in very course grain and then incrementally refined with each pass. Hit "STOP" at any time to go back to modeling.

Technical Notes

Since this ray tracer has been written in Java and is meant for the broad Internet audience with short attention span, substance has been somewhat sacrificed for form. In particular, the user does not have control over many fine aspects of the ray tracer. On the other hand, the friendly GUI allows for complex scene creation in under a minute.

Some features of this ray tracer:


The Interactive Ray Tracer was written in Java by Alyosha Efros as a class project in CS 433 (Spring 1997) at the University of Utah tought by Pete Shirley.