Questions tagged [mesh]

Questions on the use and creation of meshes including the use of MeshRegion, ElementMesh, and TetGenLink.

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2 votes
1 answer
70 views

How to import and render this OBJ file with correct texture?

Here's the output of a 3D scan of a bike, I need to render it in color with the texture file provided. Here are the files: ...
5 votes
0 answers
82 views
+100

How to reconstruct 3d meshes from 2d images of a scene?

The new ImageStitch was nice functionality added in v13, but is there anything available for constructing meshes (with color textures) from a bag of 2D images (...
4 votes
2 answers
458 views

Tracing the existing curve with star symbol

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3 votes
2 answers
99 views

Defining Dirichlet Boundary Conditions on an Imported 3D Object with Apertures in it

I am trying to simulate a static electric field (in 2d and 3d) as it passes through a couple of apertures in a 3D "metal sheet" (model imported as a .obj file) given here: https://www....
0 votes
0 answers
41 views

How to Plot a Second Dataset onto a Voronoi Diagram [closed]

I have the Voronoi diagram code working for the set of points in data1. I'd like to plot the points in data2 on the Voronoi diagram and show them in red. Any assistance is most appreciated! ...
1 vote
1 answer
140 views

Properly Updating Particle Motion in 3D Electric Field Simulation

I have a code (very bottom of post) which plots a static electric field as it passed through some metal sheet with an aperture in it. I seek to observe the motion of some N charged particles (point ...
6 votes
2 answers
212 views

Extract 2D quad mesh from 3D hexahedral mesh

I would like to extract 2D mesh of outer surface of 3D meshed object. Let's say I have 3D mesh data from here and I import the data into Mathematica. ...
3 votes
2 answers
116 views

How to refine FEM mesh for steady state 1D problem?

I am solving a system of 3 steady state 1D ODEs, however the system consists of component that has sharp changes at x = 1, which is very hard to capture. Is there a way to specifically increase the ...
0 votes
1 answer
102 views

Finite Element NDSolve with input data at node points

I am trying to solve a steady-state advection-diffusion problem of the following form: $-D \nabla^2 T + \nabla \cdot (\mathbf{u} T) = -1$. I will be solving this problem in a 3D geometry (typically ...
4 votes
1 answer
70 views

3D Mesh refinement near sphere boundary and on surface revolutions

I am trying to solve an advection-diffusion problem inside surface of revolutions. I have high velocity gradients near the boundary of the bounding surface. Is there a way to refine the mesh near the ...
3 votes
1 answer
77 views

Error Meshing with ToElementMesh (ToElementMesh: Cannot set region holes.) for certain objects

I have had a problem properly meshing certain .obj files, where others are meshed successfully. Here is an example of a successfully meshed .obj: Whereas, using the code at the bottom which includes ...
2 votes
1 answer
60 views

RegionDifference Fails at Two Simple Cubes

Or, maybe, I just dont get it right. I got two simple mesh cubes: ...
21 votes
1 answer
1k views

How to access FEM shape functions

A couple of days ago I asked here about surface meshes and plotting on surfaces. Now I have another question: How can I access the surface or boundary element shape functions? I would like to ...
3 votes
1 answer
72 views

Keeping mesh coordinates unchanged for Implict Region [duplicate]

I am trying to generate a 3D mesh for Finite Element simulations. I need to provide some precomputed inputs to the mesh points and will like my mesh to be the same for a given shape. However, ...
6 votes
2 answers
233 views

Coarse mesh of a sphere

I try to mesh a sphere (examplary) in different qualities, using MaxCellMeasure: ...
4 votes
1 answer
94 views

Finding sub-regions in an STL file for Finite Element

I use an external software (Amira) to segment X-ray tomography images and then create a surface mesh which I can then import into Mathematica as an STL file. This file has two enclosed regions, ...
3 votes
1 answer
162 views

Generating a non-convex polyhedron from polygons and normals

I am working on developing "directional offset" module, which requires pretty tricky mesh generation: offset values vary in different directions. Suppose I have list of points and polygons, ...
2 votes
1 answer
62 views

Cannot DiscretizeGraphics[] Parallelepiped nor Hexahedron

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0 votes
1 answer
51 views

3D Parametric Plotting for N Charged Particles in a Nonuniform Electric Field

I have a code (very bottom of post) which plots a static electric field as it passed through some metal sheet with an aperture in it. I seek to observe the motion of some N charged particles (point ...
0 votes
0 answers
61 views

Meshing Error on Imported obj file

I am trying to import a .obj file to be used in a static electric field simulation. I am able to successfully run the simulation with certain other aperture geometries (see here: < https://www....
4 votes
2 answers
184 views

Finding Mesh Cell Normals

I need to find a normal pointing outside for every face / cell of a closed Mesh Region. How can I do this? Here's what I have now - mesh + mesh cells centers and I'm stuck and puzzled. There's ...
1 vote
0 answers
42 views

Meaning of MeshCells for CantorMesh?

Let cantor2 = CantorMesh[2] As expected: RegionBounds[cantor2] (* {{0., 1.}} *) And as expected: ...
7 votes
2 answers
292 views

Poor/wrong sampling in 1D DiscretizeRegion of splines?

Bug introduced in 10.1 and fixed in 11.3 Context In relation to this question I have would like to use splines to define a ...
0 votes
0 answers
68 views

Difference between a region and its convex hull

I have a volume enclosing a certain region. The region is non-convex, and I calculate its convex hull with the built-in Mathematica function. I want to know the difference between the region and its ...
9 votes
1 answer
567 views

FEM Mesh for pipes and tubes

I work with pipe systems and would like to use finite elements within NDSolve for regions inside or exterior to a pipe. How to do I make a mesh of the region ...
4 votes
1 answer
127 views

Creating Voronoi Mesh Region Bounded by Convex Hull (Possible problem with DiscretizeGraphics)

I want to create a MeshRegion that is VoronoiMesh bounded by the associated ConvexHullMesh. I followed the procedure in the answer for this post, but the resulting MeshRegion is very wrong. This is ...
3 votes
1 answer
93 views

Is it possible to solve a differential equation with a user-defined variable mesh in NDSolve?

For some differential equations, its solution may evolve to a cusp, for example, singular behavior. One may want to introduce additional mesh points near the cusp to accurately follow the solution ...
1 vote
2 answers
88 views

ArrayPlot3D mesh customization

I am trying to visualize a few 2D arrays in ArraryPlot3D. I think I have made it work, however, there is a minor detail on the mesh of the plot I want to improve. For example, this is what the current ...
5 votes
2 answers
243 views

Modified Heat Transfer in Fluid Flow

I am trying to simulate Modified Heat Transfer in Fluid Flow (based on Buoyancy-Driven Flow in a Square Cavity ). The modified heat transfer takes the form: with the solid volume fraction: The ...
9 votes
2 answers
195 views

ConvexHullMesh inconsistency for the decagon

Bug introduced in V12.1.0 or earlier. Fixed in V13.0.0 or earlier. I am seeing an inconsistency in ...
4 votes
3 answers
340 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 ...
8 votes
3 answers
336 views

How to generate a mesh in an area with curves inside

I would like to know how to generate a mesh inside an area, and be able to find the original curve outline inside the area from the mesh. For example: There is a rectangle inside which there is a ...
2 votes
1 answer
223 views

Neumann boundary condition ignored

Im trying to solve a system of two PDE (im[t,x] and ia[t,x]) that are dependent on time and distance. I’m using my own anisotropic mesh (thanks to @TimLaska) that is aimed to represent an interface ...
6 votes
3 answers
554 views

1D mesh generation for PDE solution

I'm trying to solve a system of two PDE that are dependent on time and distance (H[x,t] and P[x,t]). I'm solving the problem using the method of lines but I want to generate myself the mesh and ...
8 votes
1 answer
375 views

Mass Transport FEM Using Quad Mesh

This question is a follow-up to my previous question and an attempt to implement @Tim Laska's excellent approach of setting up an anisotropic quad mesh. I'm solving a similar problem to @Tim Laska's ...
8 votes
3 answers
764 views

Unable to compute the area of region

For a set of data: ...
4 votes
1 answer
796 views

Transforming a region obtained with RegionPlot

I have a region r0, obtained from an interpolated function, with the use of RegionPlot. Let's call this function under the ...
2 votes
2 answers
565 views

Time-dependent mesh deformation

I want to display the result of a deformation with a mesh, but I solved the deformation with a time dependency. So I have two functions: uxsol[t,x,y] and ...
4 votes
1 answer
631 views

Meshing of a cube

I want to mesh a cube and what I use is ToElementMesh[Cuboid[ {-1, -1, -1}, {1, 1, 1}]]. This creates a regular grid of the cube. Is there a way to specify that ...
4 votes
2 answers
158 views

For "RegionPlot", how to fill lines, points, or grids in different areas?

For "RegionPlot", how to fill lines, points, or grids in different areas? I have tried "Mesh", but it fills all region in same mesh. I want to get the result just like this picture,...
6 votes
3 answers
217 views

Sometimes Region can't build right region

During my work with NDSolveFEM I found strange behavior of function Region. ...
5 votes
2 answers
245 views

Count number of connected regions/meshes

I want to count number of connected region. For ex I have a region below which has 2 connected region. And also, How to check whether the function ...
4 votes
2 answers
276 views

How to obtain the neighboring lists of triangles for a given triangulation [duplicate]

I have asked this question before in my previous post, but I'm still unable to generate the coding. I'm new to Mathematica and I am currently still having some troubles generating the code for finding ...
8 votes
1 answer
214 views

Quarter a given triangular meshregion

For a given , examplary simple, triangular meshregion ...
2 votes
1 answer
288 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, ...
3 votes
2 answers
243 views

Getting an Accurate Transformed Region (Part II)

I asked earlier about transforming a set of curves and getting an accurate plot when a curve goes to infinity: Getting an Accurate Transformed Region Here is an example where a transformed region ...
3 votes
1 answer
376 views

Mesh a hollow cylinder

Questions seems to be simple answerde, but in Mathemtica v11.0.1 I didn't find a solution ...
0 votes
1 answer
82 views

BoundaryDiscretizeRegion Plots does not work with ParametricPlot3D

I am trying wit this data ...
4 votes
2 answers
260 views

Making a 3D-solid from RevolutionAxis

I have the following 3D-model: RevolutionPlot3D[Sqrt[E^-x (1 + E^x)^2], {x, 0, 4}, RevolutionAxis -> {1, 0, 0}] Is there a way to make this model into a solid ...
4 votes
3 answers
274 views

Extrude two dimensional list with thickness n

I have a question concerning how to extrude a two dimensional list. There are examples in mathematica forums how to extrude but none of them (as far as i know) discussed how to do it with a list. My ...

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