Sketcher: Vincolo Coincidenza di punti
|Posizione nel menu|
|Sketch → Vincoli → Coincidenza|
|Introdotto nella versione|
|Blocca, Punto su oggetto|
Affixes a point onto (coincident with) one or more other points. introduced in version 0.21: It acts as a concentric constraint if two or more circles, arcs, ellipses or arcs of ellipses are selected.
- Do one of the following:
- Select two or more points.
- Select two or more edges of circles, arcs, ellipses or arcs of ellipses.
- There are several ways to invoke the command:
- Press the Constrain coincident button in the toolbar.
- Use the C keyboard shortcut.
- Use the Sketch → Sketcher constraints → Constrain coincident entry in the top menu.
Alternatives to Coincident constraint
The two constrained items of a Coincident constraint must be start point or end point vertices, or center points of arcs, circles or ellipses. Some combinations which are not possible with a coincident constraint can be emulated using other constraints:
- The Symmetric constraint can be used to place a start point, end point or center point on the midpoint of a straight line.
- A midpoint-to-midpoint placement of two straight lines can be achieved by creating a new Point and using two Symmetric constraints so that it lies on the midpoint of both lines.
- A vertex can be constrained to lie along an edge using a PointOnObject constraint. Note that with this constraint, the point can lie anywhere on the full extension of a segment or curve (i.e. also before the start point or beyond the end point).
- A collinear placement of two straight lines can be obtained by applying a Tangent constraint to them, or by combining a PointOnObject constraint and a Parallel constraint.
- Two edges can be made identical by using two Coincident constraints, one for each pair of extremities.
- Two circles can be made identical by using a Coincident constraint to merge the centers, and applying an Equal constraint to their edges. For arcs, this will ensure both arcs are part of the same circle, while allowing them to have different start and end points.
Il vincolo può essere creato dalle macro e dalla console python utilizzando il seguente comando:
The constraint can be created from macros and from the Python console by using the following command:
Sketchè un oggetto schizzo.
LineFixedè il numero della linea, che non deve muoversi applicando il vincolo.
PointOfLineFixedè il numero del vertice della linea
LineFixedche deve soddisfare il vincolo.
LineMovingè il numero della linea che si sposterà applicando il vincolo.
PointOfLineMovingè il numero della linea
LineMovingche deve soddisfare il vincolo.
As the names
LineMoving indicate, if both constrained vertices are free to move in any direction, the first one (first to be selected in the Gui) will remain fixed and the other one will move. In the presence of existing constraints, however, both edges may move.
The Sketcher scripting page explains the values which can be used for
PointOfLineMoving, and contains further examples on how to create constraints from Python scripts.
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