Questions tagged [mesh-generation]

The generation of a set of interconnected geometric objects that approximate a desired domain or region in euclidean space.

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18
votes
2answers
5k views

Unstructured quad mesh-generation?

What is the best (scalability and efficiency) algorithms for generating unstructured quad meshes in 2D? Where can I find a good unstructured quad mesh-generator? (open-source preferred)
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7answers
1k views

Scripted Mesh Generation Software

I'm looking for a mesh generation software that is free and open source, provides a sane scripting interface for domain specification, works for complex geometries, can generate 2D and 3D meshes, ...
12
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3answers
2k views

finite volume method: unstructured mesh vs octree adaptation + cell cutting

I'm working with the OpenFOAM C++ Computational Continuum Mechanics library (it can deal with fluid-solid interaction, MHD flows...) which uses arbitrary unstructured meshes. This was driven by the ...
12
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3answers
12k views

Meshing 3D surface data in python

I have a dataset of 3-dimensional points for which I'd like to construct a mesh, using python. All the software I've seen requires that you provide the edges. Is there a program in python which takes ...
11
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1answer
5k views

What is a “hanging node” in the finite element meshing?

When reading literatures about finite element method, the term "hanging nodes" can often be encountered. Could anyone tell me what indeed is a hanging node?
11
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3answers
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Best Methodologies for Managing a Mesh in Parallel Finite Element Computation?

I am currently developing a domain decomposition method for the solution of the scattering problem. Basically I am solving a system of Helmholtz BVPs iteratively. I discretize the equations using ...
10
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3answers
1k views

N-dimensional Delaunay Tesselation Software Libraries

I have a set of known points/nodes irregularly spaced in N-Dimensional space (N>=2), and I would like a way to generate the Delaunay triangulation of these points, and return the corresponding ...
9
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2answers
321 views

Commonly-used metrics to quantify the irregularity of a triangular mesh

Say you have a triangular mesh on a flat plane. This has been drawn to eventually solve some problem in mechanics, for example. A mesh of equilateral triangles is the best inasmuch as the distances ...
9
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1answer
267 views

Resources on mesh generation for finite element methods

I know that this is not really apart of the rules as this is a recommendation question and these don't really have an answer per say. But, like this forum posting: https://stackoverflow.com/questions/...
8
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2answers
206 views

How many cells/elements do I need?

I'm relatively new in the CFD modelling and I'm making a VOF model of a rectangular box ($l \times w \times h = 120\times 80 \times8$ m) with an inlet ($w\times h = 10\times 8$) at the long side. ...
8
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2answers
435 views

Octree cubes to tetrahedrons

I'm trying to learn more about volume meshing and have decided to try to implement a simple volume mesher. The strategy I have chosen is to subdivide my space using an octree, refined based on some ...
7
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1answer
271 views

Does some form of documentation of GMSH exist?

I am looking to implement GMSh into a simualtor that I am going to create. I am looking to integrate the geo, mesh, and post processor modules. However, looking online, it appears the documentation ...
6
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1answer
324 views

What efficient algorithms are there to generate arbitrary dimensional meshes of simplices?

I know that delaunay triangulation can be extended into arbitrary dimensions by solving the convex hull problem in $(p+1)$ dimensions and projecting the lower hull into dimension $p$ to obtain a mesh ...
6
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2answers
930 views

Is there any 2D shape repository?

As far as I see, there are many repositories for 3D shapes. But in FEM and many other applications, a planar mesh domain is also very common. However, I did not find a mesh repository specially ...
6
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3answers
662 views

Surface Mesh Library

I'm thinking a bit about the Front Tracking method used for simulation of Two phase flow with sharp interfaces. The literature tells me that the main issue is the surface mesh representation (...
6
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1answer
7k views

How to set up the dynamic mesh for a piston moving through a tube of variable diameter?

The tutorial case incompressible/pimpleDyMFoam/movingCone describes a cone moving through a "tube" (if you change the far-field patch into a wall) of constant ...
5
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4answers
3k views

Need a simple mesh format (for FEA) and a tool to generate the mesh

I want to write a 2D FEA code for my course project and I need to import a mesh (2d, simple quad/tri) on a simple geometry such as a L shaped plate or with a square/circular hole in it, something like ...
5
votes
2answers
495 views

Unstructured mesh vs hybrid structured/unstructured for numerical simulations

While answering one of the questions on meshing process, I encountered a lack of understanding on my end for the comparison of the mesh quality. First, consider an unstructured mesh created in GMSH ...
5
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4answers
1k views

Mesh generator that can do 2D & 3D elements combined?

I'm trying to analyze a circuit card assembly (CCA). The biggest problem is always trying to mesh the thin copper layers along with the thicker epoxy layers between. I'm making the approximation that ...
5
votes
2answers
388 views

Finite element discretization of Reaction-diffusion problem with Dirac source term

I'm writing a code using continuous piecewise linear finite elements on triangular grids to solve the diffusion-reaction problem. the source function f is a Dirac mass at the center. How can i compute ...
5
votes
1answer
3k views

A simple function for generating a nonuniform mesh in 1D with fixed minimum spacing

I am solving an advection-diffusion problem where the solution variable is mostly flat apart from a small region near the centre of the domain where there are shape gradients. I would like to generate ...
5
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2answers
2k views

Minimal surface solution in Python

Note: this question was also posted in StackOverflow and math.stackexchange. I have a set of 3D points defining a 3D contour, as shown below. The points in this contour lie in their best-fit plane ...
5
votes
1answer
161 views

How do you mesh and re-mesh a surface (2-manifold) in 4D?

For ease of explanation, suppose that you began with a two-dimensional surface in (x1, x2, x3, x4)-space, and the surface begins as a flat planar region in the (x1, x2)-plane. The boundaries of this ...
5
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1answer
991 views

Finite Volume Implementation

I am trying to implement a simple finite volume method solver. I had a class on FVM a while back, but am still aware of the principal concepts. But implementing the FVM for non-cartesian or 1D meshes ...
5
votes
1answer
255 views

Mesh Generation in 1-D

I am using the method by Brandt in the FAS Multigrid algorithm to estimate the truncation error in a 1-D flow problem and then use that as the basis for generating a mesh(r-adaptation) in 1-D. The ...
5
votes
1answer
988 views

Meshing options to generate number of the sides of and element (tetgen-triangle)

I wrote a finite element code in fortran 90. This code is really fast, except the meshing process. I used triangle and tetgen for meshing in 2D and 3D, respectively, so this process is fast, of ...
4
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2answers
540 views

3D contour mesh computation

I have the value of a function in three dimensions, $f(x, y, z)$, which varies smoothly. I would like to compute a 3D mesh where $f(x, y, z)$ has a particular value. Are there algorithms to do this? ...
4
votes
1answer
2k views

Is there a mesh generator that will generate zero thickness elements for interfaces?

I have a geometry and a finite element method where there are a couple internal interfaces across which I want to enforce some fairly simple jump conditions. One recommendation I've gotten has been ...
4
votes
2answers
2k views

Mesh simple 2d CAD boundry drawing

I sincerely apologise if this question is a duplicate. Though it is clearly a question that must have been asked and answered a 1000 times I can't find any reasonable solution. How do I take a simple ...
4
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2answers
3k views

Creating 3D Mesh from stl files with gmsh

After long hours of searching for an answer I thought it might be better to ask the community. The problem I have is that I need to convert STL files to mesh files. I know that I therefore need to ...
4
votes
2answers
113 views

Numerically solving a PDE on an unit tangent bundle

Let $M$ be a manifold and $UT(M)$ its unit tangent bundle. I have a PDE which looks something like $$ \frac{\partial f}{\partial t}(x,v) = (v\cdot \nabla_x) f(x,v) + \Delta f(x,v) $$ where $x\in M$, $...
4
votes
1answer
523 views

Relationship between number of nodes, elements and sides in a triangular 2D mesh

Say that N is the number of nodes, E the number of elements and S the number of sides in a triangular 2D mesh. Is there a relationship that links these quantities, possibly taking into account that ...
4
votes
4answers
153 views

Can the mesh generation methods in FVM and FEM be totally based on the knowledge of the mesh generation theory in computer graphics?

The main references of mesh generation methods in computer graphics (CG) I found are discrete Differential Geometry [1] and a famous book "Polygon Mesh Processing" [2], while the "...
4
votes
1answer
67 views

Definition of Lagrange nodes in Gmsh

When gmsh uses higher-order tetrahedral elements, there is an underlying Lagrange basis used to specify the map from reference space to the element. I'm trying to load a gmsh mesh of 3rd degree ...
4
votes
1answer
1k views

Using Gmsh to create a mesh with zero thickness (quad) interface elements

I acknowledge the following post where a similar question is posed and a very nice answer has been provided: Is there a mesh generator that will generate zero thickness elements for interfaces? ...
4
votes
1answer
609 views

metis partitioning for structured multi-block grids

Metis is purpose-built for partitioning graphs and unstructured meshes one uses in finite element/volume methods, and it works great for this. I have a 3D structured multi-block topology, where each $...
4
votes
0answers
690 views

Meshing two parts together [closed]

I have two parts, which need to be meshed. One part is located inside another. To simplify the problem, imagine two cubes: one inside another. Geometries are stored in STL files. From CAD point of ...
4
votes
0answers
463 views

Large meshing with tetgen

So I have a point cloud that I am creating a 3D flat rectangular surface from. I'm then turning it into a hollow box and connecting the corners by just dropping this surface mesh down. I need it to ...
3
votes
2answers
2k views

Survey on automatic structured mesh generation tools

I would like to gain knowledge on available free or commercial tools to generate automatically structured mesh from geometry, particularly quadrilateral. Which options do I have ?
3
votes
2answers
176 views

Why FVM can handle unstructured meshes while FDM cannot?

How come Finite Volume Method(FVM) handle the unstructured meshes and Finite difference Method cannot, whereas in FVM to approximate the fluxes at the boundary we use the central differencing? My ...
3
votes
2answers
205 views

Minimum number of elements (mesh size) for electromagnetic simulation

Does someone have a reference for the minimum number of elements (or maximum mesh size) for electromagnetic simulations where a mathematical or numerical explanation is given? I have found several ...
3
votes
1answer
261 views

Is there any open-source code for a hybrid 2D mesh (triangles and quadrilaterals)?

The question is pretty much the title. Note that I have lots of experience using open-source meshing tool, e.g. Gmsh and OpenFoam blockMesh & snappyHexMesh. Nevertheless, I have no idea on how to ...
3
votes
2answers
723 views

How to calculate efficiently mesh edges midpoints?

I have a 2D mesh of triangles used in Finite Element method to discretize the domain. I want to calculate the midpoints of all the edges because I want to use $\mathbb{P}^2$ elements. I am using ...
3
votes
2answers
1k views

Looking for a library or algorithms to perfom clipping 3D unstructured meshes by a set of surfaces

We have a 3D (volume) unstructured, possibly hybrid, degenerative irregular mesh data structure that we are capable of generating (mostly composed of hexahedra and general polyhedra, using a mix of ...
3
votes
1answer
125 views

Single nodes after mpmetis partitioning

I was checking partitioning capabilities of Metis (mpmetis) when I noticed, that it leaves two single nodes. I have marked them in red Have you seen something similar or maybe it is my mistake? The ...
3
votes
1answer
618 views

Library for polygon processing in 3D

I need to process some polygons in 3D. They are typically loaded from an OFF or STL file. Then I need to do some transformations (rotation, move, resize), I'd like to check whether points are inside ...
3
votes
1answer
578 views

Is it possible to remesh with gmsh?

I am currently working on remeshers for my simulations (academic purpose) and I try to find a method to remesh previous meshes using Gmsh. The first mesh (normalMesh.msh) was created using a .geo file ...
3
votes
1answer
249 views

Compute mesh of the projection of a 3D surface triangulation

Given a triangulated surface in $\Bbb{R}^3$ we can simply project it on a plane. This will result in a family of triangles which do not form a mesh of the projection for the following reasons: each ...
3
votes
1answer
3k views

Custom Mesh Sizes in GMSH [closed]

I have a simple question today. I am new to GMSH and I am currently learning how to use the software program. I am using GMSH 3.0.4. What I am looking to do is to set a different mesh size for ...
3
votes
1answer
126 views

Mesh with constraints

Is it possible to construct a constrained tetrahedral mesh of a domain using Tetgen or similar software? What I mean by constrained is that there are some nodes or edges that are not free but are ...