Draft Snap/zh-cn

描述
Draft Workbench tools allow you to pick points, distances, radiuses, and angles graphically by clicking on the 3D view with the pointer.

However, when these parameters need to be precise, it is possible to enter the exact Draft Coordinates in the dialog for the tool.

Another way of selecting more precise points is by using snapping. Snapping means "gluing" your next point onto an existing point or feature of another object.

Snapping is available with most Draft and Arch Workbench tools, and can be enabled and disabled globally with the button, located in the snap toolbar, which can be made active with the menu. Each snap method can be enabled or disabled individually by clicking the corresponding button on the toolbar.

While using many snapping methods at the same time can be useful to draw your objects in the desired positions, it can also be problematic if your cursor attaches constantly to the wrong points. If this is the case, try using only one snapping method at the time.



Available snap locations

 * [[Image:Snap_Near.png|32px]] Near: snaps to the closest point or edge on the nearest object.
 * [[Image:Snap_Extension.png|32px]] Extension: snaps on an imaginary line that extends beyond the endpoints of line segments. Hover the mouse over the desired object to activate its extension snap.
 * [[Image:Snap_Parallel.png|32px]] Parallel: snaps on an imaginary line parallel to a line segment. Hover the mouse over the desired object to activate its parallel snap.
 * [[Image:Snap_Grid.png|32px]] Grid: snaps to the intersections of the grid lines, if the grid is visible.
 * [[Image:Snap_Endpoint.png|32px]] Endpoint: snaps to the endpoints of line, arc and spline segments.
 * [[Image:Snap_Midpoint.png|32px]] Midpoint: snaps to the middle point of line and arc segments.
 * [[Image:Snap_Perpendicular.png|32px]] Perpendicular: on line and arc segments, snaps perpendicularly to the latest point.
 * [[Image:Snap_Angle.png|32px]] Angle: snaps to the special cardinal points of circles and arcs, at 45° and 90°.
 * [[Image:Snap_Center.png|32px]] Center: snaps to the center point of arcs and circles.
 * [[Image:Snap_Ortho.png|32px]] Ortho: snaps on imaginary lines that cross the last point, and extend at 0°, 45° and 90°.
 * [[Image:Snap_Intersection.png|32px]] Intersection: snaps to the intersection of two line or arc segments. Hover the mouse over the two desired objects to activate their intersection snaps.
 * [[Image:Snap_Special.png|32px]] Special: snaps on special points defined by the object.
 * [[Image:Snap_Dimensions.png|32px]] Dimensions: shows temporary X and Y dimensions while snapping.
 * [[Image:Snap_WorkingPlane.png|32px]] Working plane: always places the snapped point on the current working plane, even if you snap to a point outside that working plane.

Advanced snapping

 * Additional snap locations can be obtained by combining two snapping methods, such as Draft Ortho and Draft Extension, that will give you a snap point at the intersection of their imaginary lines.
 * Other snap locations can be obtained by using Draft Constrains, that is, by holding or pressing,  or  while drawing.
 * Press while drawing to insert a "hold point" at the current location of the cursor. You will then be able to snap orthogonally to these hold points, and at the intersections of their orthogonal axes. If Draft Midpoint snapping is enabled, you will also be able to snap at the mid distance between any two hold points.

Options

 * [[Image:Draft_ToggleGrid.png|32px]] Toggle grid: turns the working plane grid on and off.
 * [[Image:Snap_Lock.png|32px]] Lock: turns snapping on and off globally.
 * The maximum distance at which a point is considered a snapping point is specified in the Draft Preferences, and can also be changed on-the-fly by pressing (increase) or  (decrease) keys.
 * Pressing while drawing locks the current angle of the line segment being drawn.