# Build a model of blocks¶

## What is a model of blocks ?¶

- A block (or a hexahedron) is a volume defined by:
8 vertices

12 edges

6 quadrangular faces

A model of blocks is a set of blocks.

- And for each quadrangle of a model of blocks, this quadrangle is:
or a free face

or a face shared between 2 blocks

## How to find a model of blocks ?¶

In this version of HEXABLOCK component, the user must find himself the model of blocks that is adapted for his geometry.

## How to create a model of blocks ?¶

When the user find the model of blocks necessary for his geometry to be meshed with hexahedra, HEXABLOCK component has a lot of tool to build this model of blocks:

- basic functions:
create one hexahedron

create a hexahedra with 2, 3, 4 or 5 quadrangles

remove hexahedra

- grid building:
cartesian grid

cylindrical grid

spherical grid

- predefined model of blocks:
for cylinder

for pipe

for two intersected cylinders

for two intersected pipes

for hemisphere

for ring

- powerfull functions:
prism quadrangles

join quadrangles

make hexahedra by revolution of quadrangles

cut an edge to slice hexahedra

replace an hexadron by a pattern

- by transformation:
translation

rotation

scale

- by symetry:
with a point

with a line

with a plane

- by merging:
of two vertices

of two edges

of two quadrangles

- by disconnection:
of two vertices

of two edges

of two quadrangles

## Example of simple model of blocks¶

**An exemple of a model with 12 blocks**