Entity selection: Selection by criterion
Relation between entities
All the entities are connected one to another by relations .
- a volume is connected to the bordering faces
- a face is connected to the bordering lines
- a line is connected to the ending points, …
Thus, it is possible to select all the lines bordering a face by selecting this face, or all faces bordering a volume by selecting this volume.
The user can also plan to select entities via common characteristics :
- lines with the same visibility, or with the same color, ...
- points carrying the same mesh point
Definition / use
One speaks about selection by criterion when the selection is carried out by:
- the intermediary of the existing relations between the various entities (points belonging to a line...)
- or the intermediary of characteristics common to several entities (faces with the same color, faces on the same surface...)
- ...
Operation mode
The selection by criterion is available to the level of selection boxes and is carried out in three phases as that is presented in the table below (and on the example presented in the following block).
| Stage | Description |
|---|---|
| 0 | From a selection box … |
| 1 |
The user :
|
| The specific selection box (with logical operators) is open | |
| 2 |
Then, he selects the entities which interested him (He chooses one of the proposed selection modes: graphic selection, by identifier or criterion) |
| 3 | And applies the selection operator to the group of entities |
)Example
To select all the lines belonging to the face 23 :
The stages of selection and management of the entities can be imbricated and reiterated.
Selection criteria
An outline of the selection criteria is presented in the tables below.
| General criteria | |
|---|---|
| The option … | allows … |
| Select all | selection of all entities |
| Clean selection | deselection of all the entities previously selected |
| Select last instance | selection of the last selected entity |
| Selection by coordinates |
selection of the nearest entity to the entered coordinates |
| Specific criteria (implying the use of the operators) | |
|---|---|
| The selection by … | allows the selection of all the entities … |
| line / face / volume | belonging to a line / face / volume |
| surface | belonging to a surface (defined by a face) |
| linear / face / volume region | belonging to a line / face / volume region |
| mechanical set | belonging to a mechanical set |
| The selection by … | allows the selection of all the entities … |
|---|---|
| color | defined by a color (…) |
| visibility | defined by a visibility (visible or invisible) |
| nature | defined by a nature (standard, in air, no exist) |
| discretization | characterized by a discretization (point or line) |
Selection operators
To manage the logical operations on the groups of the selected entities, the user disposes the selection operators introduced in the table below.
| Operator | Function |
|---|---|
| Exclude | to remove entities from the list |
| Union | to add entities in the list |
| Intersect | to carry out the intersection of two groups of selection |