Questions tagged [mesh]
Questions on the use and creation of meshes including the use of MeshRegion, ElementMesh, and TetGenLink.
4
votes
3answers
224 views
How to create “Volumemesh” from closed “surfacemesh”?
Given a surface region (MesgRegion netz2D), for example
...
3
votes
2answers
71 views
Making NDSolve choosing by itself a spatial meshing leading to correct integrated results
In a previous post, I was asking how to force a fine spatial meshing in NDSolve using the FiniteElement method. The solution was
...
4
votes
3answers
73 views
Forcing at least $n$ spatial steps in solving a 1D spatio-temporal PDE problem with NDSolve
I want to solve the telegraph equation with a spatial discretization forced at 200 points. I tried:
...
4
votes
2answers
397 views
How would I define a region with multiple holes?
I would like to define a region consisting of a polygon with eight holes in it. This is essentially a stamped piece of metal with eight holes.
...
18
votes
3answers
346 views
0
votes
0answers
26 views
Using a mixture of QuadElement and TriangleElement in ElementMesh
TL;DR
Is it possible to have a ElementMesh made of a mixture of a TriangleElements`` andQuadElements`
Setup
I've got the ...
5
votes
1answer
46 views
How to not show line mesh elements
Let's say I make a mesh from a collection of random points:
SeedRandom[1234]
points = RandomReal[1, {20, 2}];
mesh = VoronoiMesh[points]
For the purposes of my ...
0
votes
1answer
39 views
How can I check to see if two cylinders overlap?
Is there a simple way for me to determine if a cylinder a and cylinder b overlap in the 3D space? I have spent a few hours ...
4
votes
1answer
45 views
3
votes
1answer
81 views
Creating a domain for NDSolveValue via ParametricRegion
A circular arc $R_2$ can be defined parametrically as $R_2 = \langle x(s),y(s) \rangle : s\in[-s_0,s_0]$ (see code below for specific $x,y$ definitions) where $s_0$ is given (I must make the arc this ...
0
votes
1answer
66 views
Understanding Energy Function [closed]
I am trying to implement as rigid as possible mesh interpolation solution provided in this article called "As-Rigid-As-Possible Surface Morphing"
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10....
2
votes
1answer
43 views
How to extract argument of MeshRegion-Object? [duplicate]
Consider examplary a MeshRegion-Object
test = MeshRegion[{{0, 0}, {1, 0}, {2,1/2}, {2, -1/2}}, {Line[{1, 2}], Line[{2, 3}],Line[{3, 4}],Line[{4, 2}]}];
Looking ...
4
votes
1answer
67 views
4
votes
1answer
68 views
Multiple Boundary Conditions for NDSolve in mesh with multiple interfaces
Here is my problem: I want to solve a Laplacian equation in a 2D geometry with multiple interfaces, each interface presenting a different boundary condition.
As for an example, I am working on a ring ...
9
votes
2answers
113 views
Distinguish between inner and outer boundary in MeshRegion
For example, this is a 2D MeshRegion with one (or more) holes in it:
...
9
votes
2answers
331 views
Picking mesh elements that are not on the border of the mesh
As an example, let's say I use a set of random points to create a Voronoi mesh
pts = RandomReal[{-1, 1}, {100, 2}];
VoronoiMesh[pts, {-1, 1}]
and get something ...
0
votes
0answers
39 views
How to get a “smoother” curve for a “discrete”-type curve?
A very interesting problem from here.
I got the algebra in less than a minute with all 6 solutions (integers). But was puzzled a bit that the graph only gives 4. As now I have waken up and tried it ...
2
votes
1answer
47 views
Information concerning undocumented function “Region`Mesh`MeshNearestCellIndex[r ]”
I'm looking for further information of the undocumented function Region`Mesh`MeshNearestCellIndex[r] (Thanks to Henrik Schumacher!)
The function considers a ...
12
votes
2answers
164 views
How to Interpolate a 3D MeshRegion?
If you were given some discrete MeshRegion called r (you don't know R):
...
5
votes
1answer
74 views
How to set a NeumannValue on a given ElementMarker on the boundary of a mesh?
How can one apply a NeumannValue on an ElementMarker on the boundary of an ElementMesh for a ...
0
votes
1answer
26 views
DelaunayMesh error : EmptyRegion
What is wrong with the following list of points?
When I apply DelaunayMesh[listPoints] I get the error ...
6
votes
3answers
97 views
Sometimes Region can't build right region
During my work with NDSolveFEM I found strange behavior of function Region.
...
1
vote
1answer
53 views
Mapping a boundary value problem: Jacobian in NDSolve and refining mesh close to a point
I would like to solve the (oversimplified!) BVP
$u''(x)-u(x)=0,\qquad x\in[0,\infty)$
with the condition $u(0)=1$. I thought to remap this into the BVP problem
$D[J^{-1}(\xi)u(\xi)]-J(\xi)u(\xi)=0, ...
3
votes
1answer
82 views
How to control boundary markers for overlapping FEM meshes?
I am trying to create FE meshes from vector or bitmap images and have come across the following issue. This is best shown using the following simplified code.
...
4
votes
1answer
142 views
How to create meshes with multiple regions from 2D images?
I would like to import 2D images to Mathematica and to use them to create meshed regions which can then be used for FEM. I create the images in Adobe illustrator so can either import a vector based ...
4
votes
2answers
111 views
How to make a frustum of a cone
For finite element purposes I need a frustum of a cone with a finite wall thickness, i.e. a tapered pipe.
To make a cone is easy
...
0
votes
0answers
47 views
How to create surface mesh from a given 2D mesh toplogy?
I would like to convert a very easy(examplary) mesh(2D)
...
0
votes
0answers
44 views
Understanding BoundaryMeshRegion error
I am trying to calculate the difference between two Cuboids:
...
1
vote
0answers
88 views
ElementMeshContourPlot and PlotLegend [closed]
Does anybody know why ElementMeshContourPlot ignored PlotLegends->Automatic? I have used the useful topic about Von Mises stress but I vould like a colored scale on the right of the plot. With ...
3
votes
1answer
88 views
ImageMesh for continuous 3D images
I have a 3D image containing distance fields, and would like to produce a mesh region from a contour at a fixed level.
I found two options for this
ImageMesh[], ...
4
votes
1answer
110 views
MeshRefinementFunction for region gives error
I would like to refine a mesh within a given path/volume, that is specified by the MeshRefinementFunction option given in ToElementMesh[].
For starting i took a simple 3D MeshRegion of a Tetrahedron
<...
7
votes
4answers
347 views
4
votes
1answer
71 views
Error in Mesh Region during concave hull
I have the following data:
Data.csv
It crates the following image:
Im trying to make a concave hull so that I can create an outline of the region. I have tried to use all versions of the ...
6
votes
2answers
121 views
Inconsistent mesh generation from BoundaryDiscretizeRegion and ToBoundaryMesh at creases
I'm trying to use BoundaryDiscretizeRegion and/or ToBoundaryMesh to generate polygonal models for 3d printing, but I'm having ...
2
votes
1answer
48 views
Difficulty with making the color gradient in the Parametric3D plot
I am making a parametric 3D plot representing a graphical solution of a nonlinear equation. This explains, why the expression is so heavy.
I would like to plot it with the color gradient such as "...
7
votes
2answers
173 views
ToElementMesh ignores Boundaries and MeshRefinemet
I'm building a mesh of a pit storage in Mathematica which I then export to another FEM-software.
I follow the workflow for creating a ElementMesh from the documentation, but it won't work in the way ...
0
votes
1answer
75 views
How to increase the thickness and change colors of the edges in a mesh?
Consider 10 random points as
pts = RandomReal[{-1, 1}, {10, 3}];
The edges of the polyhedron formed by these points can be visualized as
...
7
votes
2answers
126 views
MomentOfInertia for Polyhedra incorrectly computed?
The moment of inertia for Regions seems to be wrongly calculated. Simple example:
...
1
vote
0answers
58 views
1
vote
1answer
92 views
Mesh does not have a valid dimension as a plotting domain in 11.0
In Version 11.0, it appears that one cannot plot over a mesh. The following code worked in Version 10.2:
...
1
vote
0answers
47 views
Options problem for 3D plots
If I'm not mistaken, the code below should produce two identical pictures of a torus. But it does not. The MeshStyle->Thick option seems to be ignored for the first. Obviously the second code ...
4
votes
1answer
191 views
Voronoi mesh from non-parametric surfaces for 3D printing
I am trying to make a Voronoi mesh from the Stanford Bunny surface for 3D printing, intended as a test case to make a Voronoi mesh from any arbitrary, non-parametric 3D surface. Related techniques ...
4
votes
0answers
77 views
4
votes
1answer
161 views
Projecting 3D Mesh Region onto 2D Plane
For vizualization purposes in a beamer presentation I would like to project a 3D MeshRegion like ConvexHullMesh[RandomReal[{-1, 1}, {50, 3}]] onto a 2D plane. How ...
4
votes
1answer
82 views
BooleanRegion with .stl files does not work
Im trying to use BooleanRegion[] on an .stl file.
The imported .stl file is called pores and is of type MeshRegion (...
3
votes
1answer
98 views
Performing queries on mesh structure in a clean way
I have the following problem, which can be stated geometrically as follows:
List all pairs of vertex coordinates in a mesh region of measure 2 (a surface consisting of triangles) where these points ...
8
votes
3answers
180 views
Trouble meshing a Corbino disc
I am trying to simulate current flow using FEM through this particular device (a Corbino disk) and I have difficulties generating the mesh for it. Here is the region:
...
3
votes
0answers
74 views
Finding the shortest distance of two points and an area
So I have a region defined by something like MeshRegion[{{0, 0}, {1, 1}, {2, 1/2}, {2, -1/2}}, {Line[{1, 2}], Line[{2, 3}], Line[{3, 4}], Line[{4, 1}]}], and two ...
10
votes
2answers
168 views
How to return the coordinates of the respective 3 vertexes of a DelaunayMesh's face?
I have a set of points pts1 and a point redPts as below:-
...
14
votes
3answers
572 views
Crop a Voronoi diagram and get a proper MeshRegion
How can I crop a VoronoiMesh (or any similar MeshRegion) to a non-rectangular region and receive the output as a ...
