Vertex and Guide Snapping

Related Information

Cloak

Grid Menu

Grid Panel

Snapping

Snapping - Guidelines and Vertices

Snapping to Guidelines and Vertices positions or orients graphics precisely relative to one another. These two snapping actions are independent and is used so long as snapping to grid is not being used.

Snapping Vertices will position a particular point (for example a corner of a rectangle or end of a line) of one graphic precisely at a defined point of another graphic. Snapping guidelines will orient or position one graphic with respect to another, for example: collinear, parallel, or perpendicular.

All visible graphics provide guideline or vertex snapping references for these actions. A graphic may be excluded from consideration as a guide with one of the Cloaking Actions available on the Cloaking submenu.

The graphic or vertex that is in motion "jumps" to the precise position when the the graphic is close to the snapping reference point. These snapping actions are "soft" as the graphic may be "pulled" away from the snap point, interactively, by continuing the mouse dragging action.

In most cases the Attributes Toolbar is the primary control element for these features. It is often more convenient to use one of these contextual controls. Deselect all graphics on your drawing to see the snapping controls on the Attributes Toolbar.

These snapping actions are accessed from the Grid Menu or the Grid Panel . Both of these interface elements are found on the Format main menu.

When Snap Vertices is selected, interactive editing of a graphic via the brown graphic handles is assisted with this snapping action. The moving handle will "seek" the vertices or corners of other graphics. Snapping will also occur at the intersection of two graphics. The brown editing handle will change to green when snapped. The color change provides a visual clue of the actual snap action.

Snapping to guidelines provides precise orientation for interactive editing and moves of a graphic. Visual on screen clues are provided when a snapping orientation action occurs.

Interactive editing guide snaps are shown on screen with light yellow lines, rectangles and circles indicating a horizontal or vertical alignment position. Alignment to the horizontal and vertical edges of the bounding rectangle of graphics is indicated with a yellow line terminated with a blue corner indicator.

Orientation guides are provided when editing the shape of a graphic. The guides are derived from straight line segments of graphics. Parallel and Perpendicular orientations are found. They are shown with light green constructs indicating the controlling master graphic for the match.

Guideline actions provided for a moving graphic are different than those performed when editing a graphic. Guide snapping when moving will provided precise oriented positioning of a graphic. This may be horizontal, vertical, or oriented. If two graphics have segments whose orientations precisely match, (for example two segments that are parallel) they will "snap" when these segments are placed on the same extended line. These matches are shown with light blue dashed lines.

Snapping sounds are enabled with the checkbox found on the Guides palette. If selected a snap sound is played to provide an audio clue each time an actual snap happens. Possible sounds are provided on the popup menu found near the bottom of the Guides palette. The sounds provided are those located in the system and user library folders for sounds. The loudness is controlled by the overall system sound volume settings.

Snapping Vertices actually locates vertices (end points and mid points of each path segment), intersections, and locations on a path or curve. Color is used as a visual clue for these different location computations. Green indicates an end or mid-point, yellow indicates a point on a path, and red indicates an intersection point. Two command keys may be used to modify this behavior, hold down the Apple-Cmd key to avoid intersection (red) snapping and hold down Control key to avoid on-path (yellow) location snapping.

The concept of a reference bounding rectangle is associated with each graphic. These are used to form neat rows or columns of graphics. This bounding "box" is a virtual rectangle not actually shown on the drawing. The corners of the box are defined by infinitely thin lines that follow the center-lines the defining shape of the graphic. This means that finite line width is not taken into account for the specification of these bounding rectangles.

All graphics visible on the drawing screen are used as possible matches for vertex or guideline snaps. It is often the case that a drawing of any size will have too many graphics contributing guidelines thereby preventing the desired graphic from presenting the definitive snap match. This situation can be improved by zooming in to the location of interest, which will naturally exclude distant graphics from the guide seeking process.

The seeking process favors proximity between the moving or editing graphic and potential guide graphics. If two guide graphics are close in their respective snap positions, slight further movement of a snapped graphic may or may not shift the actual snap metrics. In any case the defining reference graphic is shown by the on screen visual alignment clue.

Snapping distance and the dynamic snapping setting control the snap action for vertices but not guidelines. See Snapping for detailed discussion of these controls.