12/3/92 Release notes for the 3-D Professional Ray Trace Module V1.00 Welcome! Please read through the notes that follow for last minute news and information which is not contained in your Ray Tracer Manual. Due to disk space limitations, the "Sample" scene mentioned in the manual could not be included. As a replacement, use your own scene, or use one of the scenes on the Data Disk. Try the "Bench" or "Thrones" scenes for starters. ADDITIONAL FILES INSTALLED Two additional files (which are NOT listed in the manual) are copied by the installation program: Tracer.fpu Tracer.fpu.info (optional) This is the floating point unit (68020/030 & 68881/882) version of the tracer. Either version may be deleted (if you are not going to use it) after installation; only one version (Tracer or Tracer.fpu) needs to be present. SAMPLE DATA The Data Disk contains some sample scenes and images. We recommend that you use this example data to familiarize yourself with the effects of the various surface attributes. These scenes can be of great tutorial value when used in this manner. There is a "ReadMe" file on the Data Disk as well which gives brief descriptions of the example scenes. THE "STARTUP" CONFIG FILE It is possible to have a config file loaded (by default) every time the tracer is loaded. If a config file with the name "startup" is in the "Configs" directory, it will be loaded when the tracer starts. This way you can customize the tracer's settings without having to specifically load or specify a config file for every trace. DO LOCAL/BATCH TRACES WHENEVER POSSIBLE We recommend that you use the ray tracer by itself as much as possible. While it IS more interactive to use the tracer as a custom renderer in 3-D Professional, there are many benefits to using the tracer alone. Refer to section 8.8 in the Ray Tracer Manual for more information on local/batch tracing. THE NEW WORLD REQUESTER Disregard section 9 in the Ray Tracer Manual. It is obsolete now that the "world" requester has been added to 3-D Professional. Refer to the latest 3-D Professional documentation (should be 1.1) for more information on the world requester. LIGHT FALLOFF EFFECT This special effect has changed since the manual was written. Instead of only affecting light which passes through transparent objects, it affects ALL light. That is, all light rays will decrease in intensity due to distance. For example, a mirrored sphere may be reflecting two objects. With this effect in use, the object that is farther from the sphere will be dimmer due to the light falloff. In the case of transparent objects, light which passes through will not only be dimmed due to distance, but also due to the object's index of refraction. Higher indices of refraction (hence harder substances) will cause light to falloff faster. NETWORK/SERIAL TRACING When doing network or serial traces, it is usually a good idea for the fastest machine to be the host. This will generally result in a more efficient tracing scenario. GENERAL PURPOSE ANTI-ALIASING For good, general purpose, anti-aliasing, try just raising the "Number of rays per pixel" setting to 4. And, leave the remaining settings at their default values. This will cause the ray tracer to use only 4 rays per pixel in most areas, but up to 32 in those areas where better anti-aliasing is needed. Please note, this will increase trace times. See section 8.5 in the Ray Tracer Manual for more information on anti-aliasing. PRODUCING AMIGA IMAGES Since the ray tracer only outputs RGB files, you will need to use either 3-D Professional or some other utility to create an Amiga image. We recommend that you output in the IFF format and use ASDG's The Art Department to convert the RGB file. The IFF RGB format is a single, compressed file and is easier to work with than the others. And, due to the nature of The Art Department, it is very good at converting RGB files into Amiga images. THE "WEIGHTED" PIXEL INTENSITY SETTING After further testing, it has been found that this option causes traced images to be of higher contrast. That is, lighter areas in the image will tend to appear even lighter in comparison to the darker areas of the image. In some cases this is a more pleasing effect. For MOST traces, however, the "Uniform" setting should be used. This is due mainly to the fact that the weighted settings requires that more than 1 ray per pixel be specified. In addition, the weighted setting will cause the trace to take longer since the number of rays actually used for each pixel will be the "maximum" in more cases. EFFECTS OF THE "RAY TERMINATION THRESHOLD" NOTE: In the manual, the default for this setting is listed as "10.0". Please note that it has been changed to "5.0". This setting represents one of the less obvious ways to adjust the "trace time/image quality" ratio. By default, the setting ensures that rays are cut off when they no longer contribute to the image in a "significant" way. The key word here is, obviously, "significant". When traced images are viewed as Amiga HAM images, they do not have nearly the color accuracy that they would if they were, for instance, viewed in full 24 bit color. This is where this threshold can come into play. By default (5.0), a good compromise is made between viewing the image in HAM OR full 24 bit. You could lower the trace accuracy by raising the threshold. This would only be a good idea if you were going to view the image exclusively in HAM (which may not be able to show the lost accuracy anyway). If, however, you are going to output images in full 24 bit color, you may want to increase accuracy by lowering this threshold. As you might suspect, lowering the value causes traces to take longer, while raising the value speeds up the trace. It is not recommended that you raise the threshold above 15.0. This would, in most cases, causes too great a loss in image accuracy and quality. LIGHTING DIFFERENCES Due to the nature of the ray tracing algorithm, specifying lighting for 3-D Professional renderings and ray traces is very different indeed. In most cases, a scene which has been both rendered in 3-D Professional and traced by the ray tracer will appear brighter in the traced image. This is especially true if the scene contains a lot of reflective surfaces. This is caused by the fact that light rays are more realistically simulated and therefore light the scene more "vigorously". You may not find that this is a problem. If so, experiment with a couple scenes and soon you'll learn to easily compensate for the differences. REPORT FILES Every time a ray trace successfully completes, a report file is written to the "Reports" directory. Report files themselves are always named "report" with a numerical extension. These files are simple, ASCII text files and can be viewed with your favorite text editor or word processor. Among archival and technical information, these files also contain the trace timings. Every now and then, you may want to clear out the Reports directory as it fills up with report files. If you do not want these files written, either delete the Reports directory or rename it temporarily. If the directory cannot be found by the ray tracer, it will quietly (no error will be given) NOT write the file.