EMAIL: agage@mines.edu NAME: Aaron Gage TOPIC: Night COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT. TITLE: Night without Day COUNTRY: USA WEBPAGE: http://www.mines.edu/students/a/agage RENDERER USED: POVray 3.0 for Linux TOOLS USED: Terrain Maker v1.0, C code written for this image, XV to convert images, tgatoppm RENDER TIME: 28h 40m 16s (5707 bogomip hours) HARDWARE USED: i486DX2/66 with 32 Megs RAM under Linux 2.0.28 (modeling) Pentium Pro with 64M RAM under Linux 2.0.29 (rendering) IMAGE DESCRIPTION: During the short minutes of a solar eclipse, the shadow under the moon becomes as dark as night; stars become visible and a chill descends on the Earth. It is an eerie time, a contradiction of night during day; the only time when the corona of the sun is visible. DESCRIPTION OF HOW THIS IMAGE WAS CREATED: Working on an animation for the IRTC (January-April, "Transportation") did not leave me more than a few weeks to work on this image, and I had even less free time than usual during those weeks. Therefore, most of the detail in this image was generated using tools, some of which I wrote for this purpose. Starting with the bottom and working up, the grass is sitting on a height- field that I created in Terrain Maker. The individual blades of grass are all from the same basic prototype; I wrote a program to generate a smooth triangle mesh of half of an inverted parabola that tapered to a point at the top. There are 90 triangles per blade of grass, and there are 2463 blades of grass in the area right in front of the camera. By using a triangle mesh, it was possible to use this many objects without exploding my memory use. The next level area, with the lake, is another height field created in TM. The water is a plane with a bozo surface normal and a dark filtering value. I thought that the water might appear too dark, but since the sky it would be reflecting is dark as well, I felt it was justified. The effect of long shadows across the water was totally accidental, but I really liked it. I believe that it was caused by the treetops that appear below the eclipse. The next region is yet another height field, created again in TM. There are 1659 triangles in each tree, generated by a program I wrote for that purpose. There are 5654 trees across the terrain in the area furthest back. In order to avoid having these trees appear too dense, I placed 88 trees around the back of the lake to break up the foreground. All of the grass and tree objects were placed as follows. I used XV to convert from Terrain Maker's .GHF GIF format to Targa. I then used tgatoppm (from the NetPBM library) to get a .PPM file of each of the heighfields. The PPM format is simple enough that I could write a program to read in color values in certain ranges and determine the height based on TM's color map. The program would then generate POV code and place trees or blades of grass at specified intervals (with some jitter) between the elevations and distances I specified, right on the heightfield at that point. This worked out pretty well. The fact that I used triangle meshes for most objects allowed me to do this without using more than 25MB of RAM at any time, and that includes three height fields and 9,747,648 triangles! (Actually, this was before I discovered the POV bug where triangle mesh textures are always relative to the origin; I changed the trunks to cones to fix this, which more than doubled my total memory use. I was forced to use a different machine to manage this increase). The eclipse is a halo and a sphere with an area light and a point light for effect. I based the appearance on some photos I found on a NASA web page: http://planets.gsfc.nasa.gov/eclipse/SEgallery/SEgallery.html The sky is a mix of a few POV textures and sky spheres. I wasn't sure if this would be on-topic enough, but I hardly had the time to do justice to the other possibilities for this round.