# Geometry building process

## Outline

An outline of the geometry building process is presented in the table below. The different steps are detailed in the following blocks.

Step Description
1 Device analysis
2 Definition of the study domain
3 Preparation of the geometric construction tools
4 Ascending construction of the geometry
5 Regrouping in regions

## Device analysis (1)

The first step of the geometry building process is the device analysis :

• to define the study domain, and
• to prepare the geometric description

The questions that could arise at this level, before starting the description itself, are grouped in the tables below (non exhaustive list).

Analysis to: Device features
define the study domain
• Does the device have geometric and/or physical symmetries or periodicities?
• Can it be studied using the infinite box feature or should we limit the study domain in a different way?
Analysis to: Device features
prepare the geometric description
• Can the device be simplified without consequences on the study physics: approximation of complex shapes, removal of rounded corners, chamfered edges, holes…?
• Does it have moving parts, variable thickness, repetitive patterns…?
Analysis to: Is it necessary
prepare the mesh
• to add points, lines, or faces in order to make easy the mesh building (skin depth…)?
Analysis to: Device features
prepare the physical description
• Does the device have specific shapes (such as thin bars, air gaps or magnetic armatures…) that can be replaced by points, lines or faces (considered as point, line or surface regions)?

## Next steps (2, 3, 4, 5)

The other steps of the geometry building process are described in the table below.

Step of …

The user
creates… builds… assigns…
Defining the study domain (2)

the symmetries

the periodicities

the infinite box

Preparing the geometric building tools (3)

the geometric parameters

the local coordinate systems

the transformations

Ascending construction of the geometry (4)

the points

the lines

the faces

the volumes

Regrouping in regions (5)

the point regions

the line regions

the face regions

the volume regions

the regions to points, lines, faces, volumes respectively

## Operations order

The different steps were presented in a “chronological” building order.

In practice, the geometry building process is not always linear and the user proceeds by successive steps. In this case, he makes “go and return” between different steps.