Meshing

Introduction

This repository contains a C++ program to open mesh files (Quad or Hexahedral meshes in VTK file format) and build a data structure for the mesh. The code can be built on Linux or Windows OS using CMAKE GUI, VTK and Visual Studio (in case of Windows OS).

Building

The code requires VTK libraries to build a meshing data structure from input VTK files, therefore, VTK (version >= 8.0) is required. The VTK source code can be downloaded from https://vtk.org/download/ and instruction to build VTK on different platforms can be found at https://vtk.org/Wiki/VTK/Configure_and_Build. To build and run the code:

• Download the repository to local machine.
• Create a new directory named build inside the downloaded repository.
• In CMAKE GUI, set source as source directory (nameOfComputer/Drive/Meshing) and set build as build directory (nameOfComputer/Drive/Meshing/build).
• Configure and Generate Make files.
• Once the Make files are generated: For Linux use make command to build executibles. For Windows open the project in Visual Studio and build.

Data Structure

The mesh data structure is organized as follows:

Vertices

A set of vertices which contain information of individual 3D points in the mesh. The vertices further have information about neighboring Vertices, Edges, Faces and Cells.

Neighboring Vertices Example

The blue vertex in the following image is the source vertex and red vertices are neighboring vertices.

Neighboring Edges Example

The blue vertex in the following image is the source vertex and red edges are neighboring edges.

Neighboring Faces Example

The blue vertex in the following image is the source vertex and red faces are neighboring faces.

Neighboring Cells Example

The blue vertex in the following image is the source vertex and red cells are neighboring cells.

Edges

A set of edges where each edge is defined by two vertices in the mesh. The edges also have information about neighboring Vertices, Edges, Faces and Cells.

Neighboring Vertices Example

The blue edge in the following image is the source edge and red vertices are neighboring vertices.

Neighboring Edges Example

The blue edge in the following image is the source edge and red edges are neighboring edges.

Neighboring Faces Example

The blue edge in the following image is the source edge and red faces are neighboring faces.

Neighboring Cells Example

The blue edge in the following image is the source edge and red cells are neighboring cells.

Faces

A set of faces defined by certain edges (4 edges for Quad and Hexahedral meshes). Each face contains information about neighboring Vertices, Edges, Faces and Cells.

Neighboring Vertices Example

The blue face in the following image is the source face and red vertices are neighboring vertices.

Neighboring Edges Example

The blue face in the following image is the source face and red edges are neighboring edges.

Neighboring Faces Example

The blue face in the following image is the source face and red faces are neighboring faces.

Neighboring Cells Example

The blue face in the following image is the source face and red cells are neighboring cells.

Cells

A set of cells which are essentially polygons (Quad or Hexahedra). In case of Quad Mesh each cell has only one face while for Hexahedral mesh, cells are built using 6 faces. Each cell contains information about neighboring Vertices, Edges, Faces and Cells.

Neighboring Vertices Example

The blue cell in the following image is the source cell and red vertices are neighboring vertices.

Neighboring Edges Example

The blue cell in the following image is the source cell and red edges are neighboring edges.

Neighboring Faces Example

The blue cell in the following image is the source cell and red faces are neighboring faces.

Neighboring Cells Example

The blue cell in the following image is the source cell and red cells are neighboring cells.