Timeline for RegionUnion Fails for Overlapping 3D Regions
Current License: CC BY-SA 4.0
17 events
| when toggle format | what | by | license | comment | |
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| Apr 20, 2020 at 9:57 | answer | added | user21 | timeline score: 0 | |
| Apr 20, 2020 at 9:55 | comment | added | Paul Harrison | @user21 Thanks, now I understand! [At least part of "the problem" is that the user is not an expert :-) ]. Perhaps this will also help with my wider problems. Will try it now. | |
| Apr 20, 2020 at 9:52 | comment | added | user21 |
@PaulHarrison, the fact that ImplicitRegion[z>=0,...] bevels the box that you specify is not wanted but a problem with the generality of the algorithm creating the mesh. Cuboid gives additional information (that the region is a cuboid, something with ImplicitRegion[z>=0,..] does not give) and a better algorithm can be used for the Cuboid case.
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| Apr 20, 2020 at 9:48 | comment | added | Paul Harrison | @user21 Thanks for the tips. I can try these. Cuboid, I had considered, but was unaware initially that if I specify explicitly a box-shaped volume, that the mesh creation would soften the corners, but not do the same to a Cuboid (which is a box-shaped region). Why would it not do the same to Cuboid? I also do not understand what putting True as an argument to ImplicitRegion does. I guess I can find it in the documentation, somewhere. | |
| Apr 20, 2020 at 9:37 | comment | added | user21 |
@PaulHarrison, I still do not understand the problem. Why do you not just use Cubiod or ImplicitRegion[True,...] to represent your region?
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| Apr 20, 2020 at 8:58 | comment | added | Paul Harrison | @user21 Ps. The reason the bevelled corners were a problem is that (as I understand it) BCs, where unspecified, are inserted as Neumann BCs. My BCs are (obviously) only specified at the main faces of the box (z==0, x=-rng etc.). The little bevelled edges effectively form 12 additional faces, which by default get their own Neumann BCs, and distort the fields in the corners. I was concerned about that and thought the best way to deal with it was to follow the (your) prescription at the SE post I linked to my original question above, which was also about similarly cut-off corners (albeit in 2D). | |
| Apr 20, 2020 at 8:46 | comment | added | Paul Harrison | @user21 I am solving a Poisson-type equation (Laplacian and load term) in 3D in the box with Dirichlet and (implicit) Neumann BCs. Hope that helps? In fact, I have found a work-around now, since I find that I can refine the corners of the box using a smaller MaxBoundaryCellMeasure, while keeping my MaxCellMeasure quite large. Probably dumb that I did not try that sooner. The workaround does not, of course, solve the bug which Szabolcs has posted for this case. (I am having another problem now, which I will post as a separate question). | |
| Apr 20, 2020 at 8:23 | comment | added | user21 | I have trouble understanding what your final objective is. Cloud you elaborate a bit on that? | |
| Apr 18, 2020 at 21:00 | history | tweeted | twitter.com/StackMma/status/1251616502232633345 | ||
| Apr 18, 2020 at 19:43 | answer | added | Steffen Jaeschke | timeline score: -1 | |
| Apr 18, 2020 at 19:38 | history | edited | Szabolcs | CC BY-SA 4.0 |
edited tags
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| Apr 18, 2020 at 19:33 | comment | added | Szabolcs |
WARNING: RegionUnion just crashed my kernel with these meshes.
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| Apr 18, 2020 at 18:51 | comment | added | Paul Harrison | @Tim Laska. This looks interesting. I will have a play with it. Thanks for your help! | |
| Apr 18, 2020 at 18:40 | answer | added | Tim Laska | timeline score: 5 | |
| Apr 18, 2020 at 17:23 | comment | added | Tim Laska | I think that you should consider using the new OpenCascadeLink. OpenCascade is an open source cad package and it does a good job preserving sharp edges on boolean operations. I showed a couple of usage examples in my answer here. | |
| Apr 18, 2020 at 16:25 | history | edited | Paul Harrison | CC BY-SA 4.0 |
Simplified example code slightly (still shows problem)
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| Apr 18, 2020 at 15:04 | history | asked | Paul Harrison | CC BY-SA 4.0 |