# Grid creating functions¶

The grid creating functions is explained in this section. Refer to Creating a grid for an overview of grid creation.

When the [Pre-processing Window] is active, grids can be created by using the menu items in [Grid] menu. Grids can be created in the following procedure:

- Select an algorithm for creating a grid.
- Set grid creating condition necessary for the algorithm using.
- Create a grid.

Operations for 2. and 3. differ by algorithm.

Table 15 shows the grid creating algorithms that can be used for iRIC.

Grid type | Item | Description |
---|---|---|

Two-dimensioinal structured grid | [Create grid from polygonal lines and width] | Creates a grid that smoothly follows a polygonal line. |

[Create grid from river survey data] | Creates a grid from [River Survey Data]. In addition to transverse lines being set, division points are set on the transverse lines the river centerline and left / right bank lines. | |

[Create geometric shape grid] | Creates a grid in a geometric shape such as sine curve by setting parameters. | |

[Create grid by dividing rectangular region] | Creates a rectangular grid that is evenly divided in the x and y directions. | |

[Create compound channel grid] | Creates a grid that has lower channel, by defining grid creating region and lower channel region. | |

[Create grid shape solving Poisson equation] | By solving Poisson equation, generate grid whose cell shape are similar to squares. | |

[Create grid shape solving Laplace equation] | By solving Laplace equation, generate grid whose cell shape are similar to squares. | |

Two-dimensional unstructured grid | [Create grid from polygon shape] | Creates an unstructured grid from polygon shape. Grid region, refinement regions, hole regions are defined as polygons. |

One-dimensional structured grid (Each node holds the cross-section data.) | [Create grid from River Survey Data] | Creates grid from River Survey Data. In addition to transverse lines being set, division points are set on the transverse lines, the river centerline and left/right bank lines. |

The common operations available for all of these algorithms are explained in Common functions. Operations specific to the algorithms are explained in [Create grid from Polygonal line and width] to [Create grid from polygon shape].

Operations available for each algorithm are accessible as sub menu item of the following:

**Menu bar**: [Grid] (G) –> [Grid Creating Conditions] (C)

- Common functions
- [Create grid from Polygonal line and width]
- [Create grid from River Survey Data] (2-D structured grid)
- [Create geometric shape grid]
- [Create grid by dividing rectangular region]
- [Create compound channel grid]
- Create grid shape solving Poisson equation
- Create grid shape solving Laplace equation
- [Create grid from River Survey Data] (1-D structured grid)
- [Create grid from polygon shape]