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Extended Object Selection

To allow more convenient object selection, three new commands were added to AutoCAD's ``Select objects:'' mechanism. These commands may be used to adapt object selection to the form best suited to a given command. The design for these new facilities draws heavily on the object selection rules in AutoSketch.

Box selection.

If you type BOX to the ``Select objects:'' prompt, AutoCAD will ask you to specify a window by two corners, as for the WINDOW and CROSSING commands. If the first point entered is to the left of the second point, BOX is equivalent to WINDOW; if the second point is to the left of the first, BOX is equivalent to CROSSING. Using BOX in a menu allows the user to choose between WINDOW and CROSSING modes simply by how the box is drawn; no keyboard entry or further menu selection is required. The BOX command must be spelled out in full; no abbreviation is defined for it.

Automatic selection.

Entering AUTO (abbreviation AU) to the ``Select objects:'' prompt chooses automatic selection. A point is requested as for single object selection. If the specified point chooses an object, that single object is the result of the automatic selection. If no object is chosen by this pick, it will form the first corner of a BOX selection as described above. Using AUTO in a menu permits the user to choose by pointing, window, or crossing simply by the way the pick is made.

Single selection mode.

The specification SINGLE (abbreviation SI) places object selection in single selection mode. This disables the normal dialogue conducted by object selection, and causes it instead to return the first object or set of objects successfully selected by a subsequent command. The ``Select objects:'' prompt will continue to be issued until a selection is made, but that selection (whether a single object or multiple objects chosen by a window) will be reported without pausing for further interaction. For example, consider the following menu item:

[Erase]^Cerase single auto

When picked, this item terminates the current command and activates the ERASE command. The selection of objects to erase is done in SINGLE mode with the AUTO selection command. In operation, the user picks this command and either points to the single object to be erased, or points to a blank area and pulls a window (crossing to the left, enclosing to the right), around the objects to be erased. This is identical to the AutoSketch ERASE command, except that it does not repeat. SINGLE selection mode leads to more dynamic interaction with the user. A complex selection may be useful at infrequent intervals, but the selection dialogue was primarily a means of confirming the object of editing commands before they performed frequently irrevocable actions. Now that a general UNDO facility is available, this is much less important.

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Next: Menu Item Repetition Up: Urgent Fury Previous: The Menu Bar

Editor: John Walker