Hi Roger ... Well done for finding the solution. I have checked and I introduced this error into the development code when I was renaming function arguments to...
4240
Roger Kaufman
vortexswirling
Feb 1, 2010 3:34 pm
Hi Adrian, ... But it will not work (for me) when I have P+P_dir. I suppose I am using it as though it were P0,P1,Q0,Q1. When I use P+P_dir the found...
4241
Roger Kaufman
vortexswirling
Feb 1, 2010 3:59 pm
Hi All, I some recent searching I came across this little "Gem". It is a collection of the code examples from some publications called "Graphics Gems" from the...
4242
Adrian Rossiter
adrianrossiter
Feb 1, 2010 6:30 pm
Hi Roger ... I have included a test program at the end of the email that checks the nearpoints on a couple of diagonals through a unit cube (that don't pass...
4243
Adrian Rossiter
adrianrossiter
Feb 1, 2010 6:41 pm
Hi Roger ... I forgot to include it. It is below. Adrian. -- Adrian Rossiter adrian@... http://antiprism.com/adrian #include...
4244
Roger Kaufman
vortexswirling
Feb 1, 2010 7:58 pm
Hi Adrian, ... Then my P_dir is really a position vector as you say. You have vec3d P0 = C100; vec3d P1 = C011; vec3d P_dir = P1-P0; but the P0+P_dir would be...
4245
Roger Kaufman
vortexswirling
Feb 2, 2010 12:13 am
Hi Adrian, ... I found this on opengl blending. I had seen it before and even have some example programs about it. This site says ...
4246
Adrian Rossiter
adrianrossiter
Feb 2, 2010 12:26 pm
Hi Roger ... I'll remove it then. ... The approach is quite difficult to follow! I didn't really get it until I had written some code. ... SGI changed the...
4247
Adrian Rossiter
adrianrossiter
Feb 2, 2010 1:00 pm
Hi Roger ... It is interesting, but it looks like the problem of blending coplanar polygons might require a bit more than this. Each plane would probably need...
4248
Roger Kaufman
vortexswirling
Feb 2, 2010 3:04 pm
Hi Adrian, ... For dealing with two triangles only, I think what I can write will be fairly efficient and not too complex. If it were to deal with large...
4249
Roger Kaufman
vortexswirling
Feb 2, 2010 7:51 pm
Hi Adrian, ... By the letter of the definition "congruent triangles" are just have the same angles and edge lengths. What I meant to say is simulataneous...
4250
Alan M
a.michelson
Feb 3, 2010 3:34 am
... Somehow, this reminds me of the discussion of the orientation of the figure-8 <http://groups.yahoo.com/group/synergeo/messages/23476?threaded=1&m=e&va\ ...
4251
Roger Kaufman
vortexswirling
Feb 3, 2010 4:32 pm
Hi Adrian, ... I have given this some more thought and the algorithm gets simpler. Redefine the problem as this. Given two triangles which intersect, the aim...
4252
Alan Michelson
a.michelson
Feb 4, 2010 7:54 am
... Actually, they might not be OK 2-dimensionally. You see, I was rotating each polyhedron along its 3-fold axis, assuming 22.5°[?] increments. But Rybo has...
4253
Adrian Rossiter
adrianrossiter
Feb 4, 2010 9:59 am
Hi Alan ... In the first image it is possible to interpret the dodecahedron and icosahedron in two positions. If you pick a face it can be on the front side or...
4254
Adrian Rossiter
adrianrossiter
Feb 4, 2010 10:24 am
Hi Roger ... That is useful as the code can be used without restrictions. I have bookmarked the page and will try to make a list of the geometry related code...
4255
Adrian Rossiter
adrianrossiter
Feb 4, 2010 10:57 am
Hi Roger ... It depends on the winding. If you join a couple of triangles that wind in opposite directions by a bridging (double) edge then you get a zero...
4256
Adrian Rossiter
adrianrossiter
Feb 4, 2010 11:43 am
Hi Roger ... I thought about the how you might solve this, and you seem to be describing what I was thinking of, except the the triangle in triangle wouldn't...
4257
Alan M
a.michelson
Feb 5, 2010 12:21 am
* GeoJourney : Messages : 2758-2761 of 3972 <http://tech.groups.yahoo.com/group/GeoJourney/messages/2758?threaded=1&\ m=e&var=1&tidx=1> * "All faces now are...
4258
Roger Kaufman
vortexswirling
Feb 5, 2010 2:09 am
Hi Adrian, ... I was looking at this a bit. First I didn't know that antiview did this! I've been looking at "winding number" and there seems to be algorithms...
4259
Adrian Rossiter
adrianrossiter
Feb 5, 2010 12:46 pm
Hi Roger ... If you mean regular polygon, in this case all the edges wind the same way around the centre. If you choose a point in some closed region and shoot...
4260
Adrian Rossiter
adrianrossiter
Feb 5, 2010 3:21 pm
Hi Roger ... Here is an example. Three prisms are joined, each sharing an edge with the other two http://www.antiprism.com/misc/orient_choice.jpg The...
4261
Adrian Rossiter
adrianrossiter
Feb 5, 2010 3:35 pm
... That should have said prism instead of pyramid (there were no pyramids!) Adrian. -- Adrian Rossiter adrian@... http://antiprism.com/adrian...
4262
Alan M
a.michelson
Feb 6, 2010 2:03 am
Each perpendicular line segment is really the cross product of the area of the face. For example, if each face were a parallelogram, then the resulting...
4263
Roger Kaufman
vortexswirling
Feb 7, 2010 2:07 pm
Hi Adrian, ... This was a bit of a panic on my part. The code works on everything unitile2d produces. But is possible to create a tiling by hand such that the...
4264
Adrian Rossiter
adrianrossiter
Feb 9, 2010 11:58 am
Hi Gerald and Marcelo ... If the strut ends are the vertices of an icosahedron then the value is phi/2 = 81% approx. On the subject of naming, I like...
4265
Roger Kaufman
vortexswirling
Feb 10, 2010 6:54 pm
Hi Adrian, I think I already know the answer to this. If I grep the src directory code for .verts() grep "\.verts()" *.cc I find that most of the places it...
4266
Adrian Rossiter
adrianrossiter
Feb 10, 2010 9:42 pm
Hi Roger ... Everything used to be get_verts(). I wanted to be able to pass geometries to functions as constants and so I needed a constant function to access...
4267
Roger Kaufman
vortexswirling
Feb 11, 2010 2:20 pm
Hi Adrian, ... Good think I asked then, because I was going to start using get_verts()! I found cases of get_verts() in c_hull.cc bravais.cc lat_util.cc ...
4268
Roger Kaufman
vortexswirling
Feb 11, 2010 2:36 pm
Hi Adrian, I have to impliment a graph traversal to find all the "internal cycles". The triangles have now been made into skeletons containing the edges of the...
