# Stage of geometry correction / simplification

## Introduction

The third stage is the stage of correction of geometric defects and/or geometry simplification.

## Correction principle

The principle of correction proposed by Flux for the various types of geometric defects is presented in the tables below:

Defect of the superposition type   Principle of correction
Confused points Suppression of a point

Superimposed lines

Cutting of the lines

Defect of the intersection type   Principle of correction

Intersection of two lines

Cutting of the lines

Intersection of a line and a face Correction is to be made by the user
Defect type   Principle of correction

Line abnormal

(value fixed by the user)

Removal of the L2 line by fusion of the lines L1 and L2

Face shorter than ...

(value fixed by the user)

Removal of the F1 face by confusion of the lines L1 and L2

Open wire

Closing of contour by prolongation of the L1 line

## Simplification principle

The principle of simplification proposed by Flux consists to remove some lines and points and thus “to reduce” the geometry. Simplification is expected only for the lines of the segment type and arc of circle type.

The principle of simplification is presented in the table below:

Geometry type   Principle of simplification

Segments located on the tangent of the straight lines

Removal of the lines L2 and L3 and suppression of the points P2 and P3 by fusion of the lines L1, L2 and L3

Arc of circle having the same curve angle

Removal of the lines L2 and L3 and suppression of the points P2 and P3 by fusion of the lines L1, L2 and L3

## Algorithms of automatic correction / automatic simplification

To facilitate the process of correction, the algorithms of automatic correction / automatic simplification are proposed. They are presented in the table below:

The algorithm of … enables the correction …
automatic correction

of all blocking defects

(superimposed entities and intersections)

automatic simplification of all defects of type: abnormal lines
Note: These algorithms are planned especially for the 2D geometry, the result in 3D is not guaranteed.

## Manual correction

To correct the other defects the user must carry out a manual correction with the tools presented in the table below. The use of these various commands is detailed in section Geometry correction / simplification of chapter Geometry / mesh importation: software aspects .

To correct the defect type ... the user should ...

Intersection of lines

Superposition of lines

Cut line on a point

Cut line on intersection

Abnormal line

Abnormal face

Decrease absolute precision by reducing relative precision (relative epsilon)

Abnormal line

(user epsilon)

Fuse lines

Abnormal face

(user epsilon)

Confuse lines
Open wire

Extend line to point

Extend line to line