---
name: "mkgeo_ball"
section: "1rheolef"
platform: "linux"
package: "rheolef"
version: "7.2-4"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/mkgeo_ball"
---

# mkgeo\_ball(1rheolef)

unstructured mesh of an ellipsoid (rheolef-7.2)

## NAME

mkgeo\_ball - unstructured mesh of an ellipsoid (rheolef-7.2)

## SYNOPSIS

```
mkgeo_ball [options] [n]
```

## EXAMPLE

mkgeo\_ball -t 10 \| geo -

The previous command build a triangle based 2d unstructured mesh of the unit ball

## DESCRIPTION

This command is useful when testing programs on simple geometries. Invocation is similar to those of **mkgeo\_grid(1)** . It calls `gmsh` as unstructured mesh generator. It avoid the preparation of an input file for a mesh generator. The optional *n* argument is an integer that specifies the subdivision in each direction. By default n=10. The mesh files goes on standard output.

## THE MESH ORDER

`-order` *int*

 The polynomial approximation mesh order, for the curved boundary, as defined by `gmsh`. Default is order=1.

## ELEMENT TYPE OPTION

`-e`

 1d mesh using edges.

`-t`

 2d mesh using triangles.

`-q`

 2d mesh using quadrangles (rectangles).

`-T`

 3d mesh using tetrahedra.

`-P`

 3d mesh using prisms.

`-H`

 3d mesh using hexahedra.

`-tq`

 2d mesh using both triangles and quadrangles.

`-TP` \
 `-PH` \
 `-TPH`

 3d mixed mesh combining tetrahedra, prisms and/or hexahedra.

## THE GEOMETRY

`-a` *float* \
 `-b` *float* \
 `-c` *float* \
 `-d` *float* \
 `-f` *float* \
 `-g` *float*

 The geometry can be ellipse/ellipsoid inscribed in the \[a,b\]x\[c,d\] rectangle or the \[a,b\]x\[c,d\]x\[f,g\] parallelepiped. By default a=c=f=-1 and b=d=g=1, thus, the unit balls are considered.

`-s`

 Only a surface mesh is generated: a curved line in 2d or a curved surface mesh in 3d. In 3d, supports both '-t' and '-q' options.

## BOUNDARY DOMAINS

The meshes defines a domain named `boundary` that groups all boundary sides.

## OTHERS OPTIONS

`-[no]fix`

 By default, internal face and volume node from gmsh are recomputed, since they have incorrect coordinate that destroy the convergence properties of isoparametric high order elements (order \>= 3). The `-nofix` option skip this correction: this option is available for test purpose.

`-[no]clean`

 Clear temporary files (this is the default).

`-[no]verbose`

 Print intermediate commands and information messages.

## IMPLEMENTATION

This documentation has been generated from file main/sbin/mkgeo\_ball.sh

## AUTHOR

Pierre  Saramito  \<Pierre.Saramito@imag.fr\>

## COPYRIGHT

Copyright   (C)  2000-2018  Pierre  Saramito  \<Pierre.Saramito@imag.fr\> GPLv3+: GNU GPL version 3 or later  \<http://gnu.org/licenses/gpl.html\>. This  is  free  software:  you  are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.