Questions tagged [mesh]
Questions on the use and creation of meshes including the use of MeshRegion, ElementMesh, and TetGenLink.
428
questions
5
votes
1answer
129 views
Area of an Annulus (MeshTools<>NIntegrate)
In a very simple example I try to describe an annulus using MeshTools package
mesh2D = AnnulusMesh[{0, 0}, { 1 , 2 }, {-Pi, Pi}, {36, 10}];
The area given ...
10
votes
2answers
306 views
Generating Mesh of Rotated Graphics
I have a simple geometry that consists of a few rotated rectangles
...
10
votes
5answers
518 views
Grainy 2D RegionIntersection Plot: How can I make it smoother?
I have the following code to display three coloured disks and their coloured intersections. However, the result does not appear to have been anti-aliased enough. How can I make it smoother?
...
2
votes
2answers
57 views
Select Part of a boundary mesh
I would like to pick a part of a boundary mesh, for example
bm=BoundaryMesh[Cuboid[]]
Is it possible to select the part(side) ...
0
votes
1answer
63 views
8
votes
2answers
134 views
How to mesh a region with inclusions touching the boundary
Suppose you have a region composed of two materials. You define the inclusions of material 1 through, e.g., disks, ellipsoids, ...
4
votes
1answer
100 views
Adaptive Meshrefinement NDSolve&FiniteElements
In a simple example I try to solve the heat equation using NDSolve and Method->"FiniteElement". I know that NDSolve gives ...
2
votes
1answer
30 views
Draw Lines on 3D Plot at certain coordinate
Following this example, I though it would be as easy as this:
...
0
votes
1answer
74 views
Nonatomic expression expected at position 1 in First[None]
This is a follow-up question to an earlier question:Solving a system of PDEs on a piecewise polynomial domain.
I tried to solve the system of equations from one of my previous post with the different ...
6
votes
3answers
457 views
Compare FEM mesh with the mesh created within Mathematica
This is a follow-up question to an earlier question: Make uniform mesh with quad elements
Question: How to solve system of equations with NDsolve on the mesh created in Ansys in order to compare it ...
15
votes
3answers
275 views
Computing the surface area and volume of molecules
Here is a somewhat difficult problem I've had for a long while.
Space-filling models of molecules can be easily generated by ChemicalData[], ...
0
votes
1answer
63 views
3
votes
3answers
368 views
Nearly equally spaced 3D-mesh
How to mesh a volume (3D region) with nearly equaly spaced vertices?
Example: Disk with radius 50 and height 15
...
3
votes
1answer
82 views
Unable to use ElementMarker in DirichletCondition with structured quad mesh
I would like to use ElementMarker in a DirichletCondition on a structured quad mesh, but I am receiving the error:
...
1
vote
1answer
56 views
Blunt edges of an octahedron by Region
Why does the octahedron constructed by the following code have blunt edges ?
Region[ImplicitRegion[Abs[x] + Abs[y] + Abs[z] <= 1, {x, y, z}]]
How to improve it?...
2
votes
2answers
133 views
How to extrude a planar mesh to a volume slice?
Is there an easy way to extrude a planar 2D-mesh to a volume slice?
ring = RegionDifference[Disk[{0, 0}, 1], Disk[{0, 0}, 1/2]];
DiscretizeRegion[ring]
The ...
3
votes
1answer
88 views
Mesh a hollow cylinder
Questions seems to be simple answerde, but in Mathemtica v11.0.1 I didn't find a solution
...
4
votes
1answer
90 views
control FEM grid size for 1D regions
I need to manage the mesh size for finite element method solution to a differential equation, where properties change over two regions. This is for one dimension. I created a boundary mesh of three ...
3
votes
1answer
79 views
RegionUnion works but RegionIntersection does not
I am trying to create an Alberti's window figure as described in this question, in which a (three-dimensional) polyhedron (e.g., dodecahedron) is projected onto a (two-dimensional) plane. I realized ...
2
votes
1answer
63 views
Unwanted mesh line in spherical plot
I am trying to create a spherical colour plot on which the mesh will rotate with manipulating the \phi1 variable. I read this solution and gave it a try with the following code:
...
1
vote
0answers
42 views
Combining MeshRegions of generated 3D shapes and RandomPolygons
I am interested in generating 3D a joint BoundaryMeshRegion or a MeshRegion from different shapes and polygons. This works for <...
8
votes
2answers
223 views
Make uniform mesh with quad elements
I have the following code that generates a finite element mesh with triangular elements which by using command ToQuadMesh I convert to the quadrilateral elements, but I am not able to make the uniform ...
1
vote
2answers
91 views
How to sample numerically a function using a mesh-grid function in 3D?
I am working on a problem where I want to sample a scalar function f[x,y,z].
The problem is how to obtain a mesh-grid in 3D (A grid of points in x,y, and z). In order to study this function.
Of ...
1
vote
0answers
102 views
Calculate the intersection points of a line and a parametrically defined 3D surface
Thanks to Henrik Schumacher for advice to simplify the sample code:
I would be grateful for any pointers on the following issue.
A line from an external point intersects the surface at 2 points (...
1
vote
1answer
108 views
How to solve wave equation with finite elements when material properties vary continuously over a region
I am solving the one-dimensional wave equation over regions where the bulk modulus (and thus the wave speed) vary continuously over a region. The current version seems to assume that the material ...
6
votes
2answers
95 views
How to refine a linear FEM mesh in three regions?
I am trying to solve the one-dimensional wave equation with a frequency dependent source function over three intervals with varying velocity. I need to refine the mesh over the low velocity regions ...
5
votes
2answers
129 views
Automatic solution to label boundary elements with BoundaryMarkerFunction
Preparations
Mathematica 11.3, Windows.
Let us say I have a rectangular region with 10 little holes inside. Their coordinates are given by positionList. The ...
1
vote
0answers
46 views
Non-convex hull mesh from 3d points [duplicate]
I am trying to create a 3d mesh object from list of points, but the only options I see in Mathematica are ConvexHullMesh and ...
3
votes
1answer
68 views
Signed cell adjacency matrices (boundary operators)
In How to obtain the cell-adjacency graph of a mesh? there are some great answers that show how to obtain the cell adjacency matrix of a mesh. How would one generalize these to incorporate the ...
5
votes
2answers
135 views
Adjacent faces in a discrete mesh
I have a MeshRegion R and I want to extract all pairs of adjacent faces efficiently. The way that I've been computing this is demonstrated below:
...
3
votes
3answers
117 views
RegionMember does not work with RandomPolyhedron or Polyhedron object
According to the documentation RegionMember should work with regions that are true for ConstantRegionQ. However, the function ...
6
votes
2answers
202 views
Extracting points from 3D plot that lie along an arbitrarily oriented line
Starting from i.e. the following 3d plot:
d = RandomReal[1, {100, 3}];
ListPlot3D[d]
Is it possible to extract points that lay along an arbitrarily oriented line,...
1
vote
1answer
78 views
Set maximum space between elements in 3D mesh
A region in 3D space has been discretized to obtain a list of points.
The resulting ListPointPlot3D plot is:
I will like to obtain a mesh from these points, but ...
4
votes
1answer
43 views
Extra Lines in 3D ConvexHullMesh
I would like to make a picture of a truncated octahedron using ConvexHullMesh as follows:
...
6
votes
1answer
156 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
70 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
76 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
82 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
72 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
64 views
4
votes
1answer
68 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
48 views
RandomPoint returns compiler errors on RegionIntersection of two Meshs?
Consider the intersection of two ConvexHullMesh's, m1 and m2.
...
4
votes
1answer
96 views
3
votes
1answer
77 views
5
votes
2answers
129 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 ...
8
votes
2answers
398 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
104 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
44 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
90 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
119 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.
...
