Graphic problem

*To*: mathgroup at yoda.physics.unc.edu*Subject*: Graphic problem*From*: wallraff at acds.physik.rwth-aachen.de (Wolfgang Wallraff)*Date*: Tue, 4 Aug 92 15:32:18 GMT

Currently I am working on a project that deals with displaying ropes as three-dimensional Graphics in Mathematica. In the past few weeks some problems occured which I was not able to solve with the original ducumentation! Problem No.1 : Displaying 2D-Polygons in 3 Dimension This Polygon in 2 dimensions display the character "W". (no problem!) a = {{0.116466, 0.73494}, {0.269076, 0.73494}, {0.353414, 0.353414}, {0.429719, 0.73494}, {0.582329, 0.73494}, {0.662651, 0.345382}, {0.751004, 0.73494}, {0.895582, 0.73494}, {0.742972, 0.176707}, {0.594378, 0.176707}, {0.51004, 0.566265}, {0.421687, 0.176707}, {0.273092, 0.176707},{0.116466, 0.73494}}; Show[Graphics[Polygon[a]]] Adding a third dimension to the vectors should result in displaying a "W" as a plane in the 3D-space: Show[Graphics3D[Polygon[{{0.116466, 0.73494,0}, {0.269076, 0.73494,0}, {0.353414, 0.353414,0}, {0.429719, 0.73494,0}, {0.582329, 0.73494,0}, {0.662651, 0.345382,0}, {0.751004, 0.73494,0}, {0.895582, 0.73494,0}, {0.742972, 0.176707,0}, {0.594378, 0.176707,0}, {0.51004, 0.566265,0}, {0.421687, 0.176707,0}, {0.273092, 0.176707,0},{0.116466, 0.73494,0}}]]] But it is not displayed in the correct way. It tried the same problem with numerous other examples, but all Polygons with numerous edges had the same problem! Last problem: Memory-requirements of Graphics3D with a large number of Polygons[] I am using Mathematica on a Macintosh II ci with 20 MB of RAM. I often get into memory-problems if I want to display Graphics with a large number of Polygons. The time for evaluating such graphics becomes long (1 hour or more). For this kind of evaluation Mathematica needs a lot of memory (20MB seem to be not enough). Because of this I would appreciate to get some information about how Mathematica processes 3D Graphics and how I could display Graphics with a lot of polygons with limited memory. Hoping that you can provide answers to my questions Andreas Wallraff wallraff at acds.physik.rwth-aachen.de