OK, I see that the POLYHEDRA command is really overkill for what I'm trying to do. I could essentially create my own polyhedral representations if the DRAW command was extended to allow the drawing of planes with an arbitrary number of vertices so that I could create triangles, pentagons, etc. as needed. Should I submit this as a feature request???
Dean On 6/9/07 12:51 AM, "Bob Hanson" <[EMAIL PROTECTED]> wrote: > Dean, sounds like you might appreciate: > http://www.scienceu.com/geometry/facts/solids/coords/ > > Well, ah, let's just say it doesn't work the way you probably think it > does. The polyhedra code is a very complex algorithm that looks at > possible faces (combinations of three atoms around a central atom) and > determines which are "faces" and which are not. We have: > > #atoms comb of 3 at a time > 4 4!/(3!)(1!) = 4 > 6 6!/3!3! = 20 > 8 8!/3!5! = 56 > 9 9!/3!6! = 84 > 12 12!/3!9! = 220 > 20 20!/3!17! = 1140 > ... > n n(n-1)(n-2)/6 > > so if you do nothing special, then you will possibly run into the > problem with any number more than 9. HOWEVER, the algorithm has a > parameter, distanceFactor, that is adjustable, and if you set it > smaller, it will work. For example (That second line should not wrap), try: > > 13 > #jmolscript: connect (*) (*) delete;connect (_Fe) (_C);select > *;wireframe off;spacefill off;select (_Fe); polyhedra bonds > distanceFactor 0.5 > Fe 0 0 0 > C -0.692 0.000 0.427 > C 0.000 0.427 -0.692 > C 0.000 0.427 0.692 > C 0.692 0.000 -0.427 > C -0.427 -0.692 0.000 > C -0.427 0.692 0.000 > C 0.000 -0.427 0.692 > C 0.427 0.692 0.000 > C 0.000 -0.427 -0.692 > C 0.692 0.000 0.427 > C 0.427 -0.692 0.000 > C -0.692 0.000 -0.427 > > As for dodecahedra, that's just too large. I've upped the maximum number > of faces to 147, and that takes care of it, but there are a few stray > lines, since we are painting more triangles than actually needed. Just > the way it goes, I guess.... > > > > Bob > > > Dean Johnston wrote: > >> Has anybody tried to create polyhedra with 12 or 20 vertices? The >> documentation seems to indicate that I should be able to go up to 20. >> >> I¹m creating representations of shapes (Platonic solids, actually >> maybe Jmol isn¹t just for molecules anymore... :-). I would like to >> display an icosahedron and dodecahedron. I¹ve created structures with >> a central atom surrounded by 12 or 20 atoms, but when I try and create >> the polyhedron, I get the following error message: >> >> Polyhedron error: maximum face(87) -- reduce RADIUS >> >> I have a feeling it¹s creating more polyhedra faces than I want it to >> (I only want 20), but I¹m not entirely familiar with how it works. >> I¹ve gotten it to work just fine for tetrahedra and octahedra. Any >> insights, corrections, etc. are greatly appreciated. >> >> My testing page is at: >> http://www.otterbein.edu/home/fac/dnhjhns/jmoltest/poly.html >> >> Dean >> >> ------------------------------------------------------------------------ >> >> ------------------------------------------------------------------------- ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Jmol-users mailing list Jmol-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jmol-users
