Timeline for How to get a list of vertices in a convex hull
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 6, 2018 at 8:13 | comment | added | user1993416 | I am going to post the problem in a new question | |
| Jun 6, 2018 at 8:07 | vote | accept | user1993416 | ||
| Jun 6, 2018 at 7:55 | comment | added | user1993416 | I would like to get the vertices of the sides of the hull without the edges of the triangles that are in the same plane. Do you know how I could get the close removing connections of vertices in the same plane or side of the figure? | |
| Jun 6, 2018 at 7:45 | comment | added | Henrik Schumacher | You're welcome. | |
| Jun 6, 2018 at 7:43 | comment | added | user1993416 | The code is beautiful. I understand why Mathematica uses triangles. Thank you very much. | |
| Jun 6, 2018 at 7:41 | vote | accept | user1993416 | ||
| Jun 6, 2018 at 8:07 | |||||
| Jun 6, 2018 at 6:48 | comment | added | Henrik Schumacher | You can "close" the the index triples in the list faces from above by closedfaces = Join[faces, faces[[All, {1}]], 2]. | |
| Jun 6, 2018 at 6:46 | comment | added | Henrik Schumacher | Mathematica uses the external library TetGen for computing convex hulls of point clouds in three dimensions. And TetGen uses tetrahedra and triangles to build geometric objects. That's actually a very good idea since all polyhedral structures can be build from that and it holds the combinatorical complexity at bay. | |
| Jun 5, 2018 at 22:54 | comment | added | user1993416 | I do not know why Mathematica uses two triangles to form a side with four vertices. This procedure will give more sides than the real figure. Is it possible to get a matrix of vertices like in the example, and use the number of vertices of the side with the highest number of vertices and repeating the first vertex at the end of the row to close the polygon? | |
| Jun 5, 2018 at 22:46 | vote | accept | user1993416 | ||
| Jun 5, 2018 at 22:46 | |||||
| Jun 5, 2018 at 22:41 | comment | added | user1993416 | Thank you for your answer. I call patch to each side of the convex hull. The code of your post works for me. I only would need to start numbering from 0 not from 1, and to close the polygon or to add the first vertex to the end of the list of vertices. For example, {1,5,8} should be { 0,4,7,0}. Is it that possible to make?. | |
| Jun 5, 2018 at 22:34 | vote | accept | user1993416 | ||
| Jun 5, 2018 at 22:34 | |||||
| Jun 5, 2018 at 22:32 | comment | added | Henrik Schumacher | Edited. Please try again. Note that I can't see any pentagons as sides of the convex hull. | |
| Jun 5, 2018 at 22:30 | history | edited | Henrik Schumacher | CC BY-SA 4.0 | added 26 characters in body |
| Jun 5, 2018 at 22:09 | history | answered | Henrik Schumacher | CC BY-SA 4.0 |