Questions tagged [mesh]
Questions on the use and creation of meshes including the use of MeshRegion, ElementMesh, and TetGenLink.
6
votes
1answer
134 views
Given a cell in a Voronoi diagram, which point did it come from? [duplicate]
Given a set of points
pts = Table[{RandomReal[], RandomReal[]}, {i, 1, 10}];
and their Voronoi diagram
...
1
vote
1answer
47 views
Mesh quality error with interpolation of table
I am trying to interpolate a table of the following form.
{{x1,y1,z1},{x2,y2,z2}...}
Where z depends on x and y, and x ranges from 0.01 to 1 in steps of 0.01, ...
4
votes
1answer
63 views
Find surrounding vertices (simplexes) of a given point for DelaunayMesh
Generating a Delaunay triangulation of some random points:
pts = RandomReal[{-1, 1}, {50, 2}];
dm = DelaunayMesh[pts];
HighlightMesh[dm, Style[0, Black]]
gives
[...
0
votes
0answers
75 views
Create a tube from a section of a sphere using mesh
How does one make a meshed tube starting from a section of a sphere and later edit the tube's section parametrically.
4
votes
1answer
61 views
Difficulty in specifying mesh refinement
I am trying to give a region within a 3D volume a finer mesh than the rest of the volume. My problem is more complicated but here is a minimum working example.
I define a 3D cuboid and try and have a ...
1
vote
1answer
61 views
4
votes
1answer
48 views
Make MeshRegion/BoundaryMeshRegion work as a graphics primitive in M11
Mathematica 12 has the nice feature that MeshRegion and BoundaryMeshRegion objects render nicely when included as a primitive in ...
5
votes
1answer
46 views
RandomPoint returns compiler errors on RegionIntersection of two Meshs?
Consider the intersection of two ConvexHullMesh's, m1 and m2.
...
4
votes
1answer
83 views
2
votes
1answer
59 views
5
votes
2answers
105 views
Holes in ElementMesh with ToElementMesh of ImplicitRegion
I am trying to plot a function in a region below a level curve of the function and within a cell. I have been doing this by calculating an ElementMesh using ...
9
votes
2answers
284 views
Catmull-Clark and Doo-Sabin Subdivision Implementations
I want to work on subdivision surfaces. Unfortunately, I don’t have any source code to start with. I need some Mathematica codes for applying Catmull-Clark and Doo-Sabin methods. I would like to ...
2
votes
1answer
82 views
Meshing control of NDEigensystem
I have to solve an Eigenvalue problem originating from the Electrodynamics. It is a 2-D problem with a rectangular region. More specifically, there is a hole on a rectangle made by magnetic material. ...
3
votes
1answer
38 views
Is there a way to automatically use triangular elements in ToElementMesh [closed]
I have some simple code to generate a mesh over a rectangle.
...
1
vote
1answer
77 views
Converting .STL from Shell to Solid for stress analysis of wing
I'm new to Mathematica as this is the first class I've had to used it in my undergrad time as an aerospace engineer. Anyway, I have run into a problem that I can't figure out. I have created .STL's of ...
2
votes
1answer
114 views
Finding the tangents of the function in each mesh
I have a 2D graphic which contains a table of curves within a circular region.
...
5
votes
1answer
55 views
Mesh cell count for Voronoi mesh too low
I was trying to solve this question out of interest and thought perhaps creating a Voronoi mesh, cropping it to a circle, and colouring the mesh cells might work. However, if I ask ...
1
vote
1answer
36 views
Uneven distribution of nodes by ToElementMesh[]
We are using FEM package to generate mesh in a circular sector. Somehow mesh becomes dense in upper right corner. Is there any way to circumvent this uneven distribution?
...
4
votes
1answer
71 views
VoronoiMesh with custom distance function
I'm failing at reading the documentation. Is there a way to specify the distance function used by VoronoiMesh? As a stripped down example say I have a rank-1 lattice such as:
...
10
votes
2answers
131 views
ToElementMesh of Region with Hole
When I try to mesh the following region it fails. Why? Is there a workaround?
...
13
votes
2answers
567 views
Meshing the cow
As a simple example for applying stl-files I took "cow" out of MMA example data. I'm able to discretize the Graphic without problems
...
2
votes
1answer
76 views
Colorize mesh according to the nodepoint colors
Given a set p of points (2D), each with a unique color c, I can mesh these points easily
...
1
vote
2answers
84 views
Trouble with Calculating Area of Parametric Region
This question stems from an attempt to solve the following question: How to calculate specific area on surface of sphere?
First, I parametrize a circular loop:
...
5
votes
3answers
248 views
How to create “Volumemesh” from closed “surfacemesh”?
Given a surface region (MesgRegion netz2D), for example
...
3
votes
2answers
89 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
85 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
414 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.
...
19
votes
3answers
419 views
0
votes
0answers
31 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
57 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
44 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
53 views
3
votes
1answer
89 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
71 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
46 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
79 views
4
votes
1answer
104 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
141 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
342 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
45 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
56 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
175 views
How to Interpolate a 3D MeshRegion?
If you were given some discrete MeshRegion called r (you don't know R):
...
5
votes
1answer
84 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
34 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
113 views
Sometimes Region can't build right region
During my work with NDSolveFEM I found strange behavior of function Region.
...
1
vote
1answer
56 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
149 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
174 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
148 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
...
1
vote
1answer
74 views
How to create surface mesh from a given 2D mesh toplogy?
I would like to convert a very easy(examplary) mesh(2D)
...
