# Tag Info

Accepted

### Shrink wrapping algorithms to make a mesh watertight for 3d printing

Making a mesh watertight There are several efficient algorithms to make a mesh watertight, historically, in Stanford, the pionneers of 3D Scanning developed the Zipper algorithm: https://graphics....
• 2,275
Accepted

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

I would recommend gmsh. I have just started working with this program actually only a few days ago. But it is straight-forward to use. You can create various 2D and even 3D-geometries and it offers a ...
• 350
Accepted

### Algorithm to find boundary faces of mesh

First, create a list of faces in the mesh. From there you should be able to create a map from faces to tets, as each face must belong to either one or two tets. The faces that belong to only one tet ...

### What is a common file/data format for a mesh (for FEM)?

The short answer is no, there is not a standard format. But there are some common ones, like Gmsh for input/output and VTK for output. Before making a decision you need to find out what do you want ...
• 8,219

### Mesh ordering algorithms used by COMSOL Multiphysics

The idea of "ordering the nodes" in a finite element mesh to improve the computational time of the sparse solver originated in the large structural analysis FE codes of the 70's. Those codes typically ...
• 5,804
Accepted

### 3D contour mesh computation

I think you could use the "marching cubes" algorithm. If memory serves, it requires a grid of samples as input, so at the very least you should be able to sample your function and run the algorithm as-...
• 4,574
Accepted

### Is mesh orthogonality important for FEM?

Yes. The constants that appear in the interpolation estimates upon which finite element error estimates are based contain minimum and maximum angles of triangles/tetrahedra (or similar geometric ...
• 52.2k

### How to "smoothen" (not just refine) a 2D/3D polygonal mesh

To complement the two answers from Daniel Shapero and Nicoguaro: Basically, there are two ways of smoothing a mesh, subdivision (generate new vertices) and smoothing (move the points in such a way ...
• 2,275

### Solving PDEs in parallel

Domain decomposition was developed in the late 1990s and early 2000s because it allowed the re-use of sequential PDE solvers: You only have to write a wrapper around it that sends the computed ...
• 52.2k
Accepted

### Unreasonably large deviation in calculations of mean curvature in different algorithms

First of all remember that curvatures, being 2nd order values, can be really sensitive to even very small variations. Moreover, we are speaking about computing differential values in a discrete ...
• 176
Accepted

### Common nodes in two FEM grids

Hashing floating-point numbers can indeed lead to weird results, especially if the node positions can be perturbed by some small amount or if there are denormalized values. You included the Python ...
• 8,835

### How to "smoothen" (not just refine) a 2D/3D polygonal mesh

As mentioned in the answer by @DanielShapero, you can follow an approach based on local approximations of the curvature for your nodes. In the post he suggest, there is an article by Desbrun. I would ...
• 8,219
Accepted

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

As @Nicoguaro and @Paul have said in the comments to the question post, there are a great many ways to do this kind of thing, and I'm not sure if there is a single "best" approach. From a review ...

### Barycentric interpolation equivalent for irregular hexahedra

A hexahedron with straight edges is the image of the unit cube under a trilinear mapping. So, if you have values on the eight vertices of a hexahedron, and you are asking to interpolate between them ...
• 52.2k
Accepted

• 11.4k

### Effect of mesh size on solution curves for a 1D problem

What you're looking for is an a-posteriori error estimate for your mesh study. Normally, these quantitative measures are line/area/volume- and/or time- averaged nodal or element quantities (e.g. avg. ...
• 570

### What are the best ways to interpolate a vector field inside (convex) polygons?

Let me try and break the problem down into two steps. Step 1: You have a polygon (one cell of your mesh) and you have scalar data $d_i$ associated with each vertex $\mathbf x_i$ of that polygon. You ...
• 52.2k