Autotek autocad raster design 2010 用户手册

Raster Snap makes it easy to select points on raster entities when you are using vectorization
tools (VTools) or REM commands.

NOTE Raster Snapping works only with bitonal images.

You can use raster snapping to move your AutoCAD cursor precisely to the center, end, corner,
intersection or edge of a bitonal raster entity. When raster snapping is on (active), Raster
Design displays a 

 (page 398) around the AutoCAD cursor. This window moves

with the AutoCAD cursor and displays the crosshairs over points you can snap to.

Raster snap modes are very similar to AutoCAD object snap modes (OSNAP), except that they
snap to raster objects instead of to vector objects. Also, Raster Snap is active only when you
are in a command and are being prompted for a point. Raster Snap settings are located on
the Raster Snap tab of the AutoCAD Drafting Settings dialog box.

Conflicts can occur between raster snapping and other utilities that control the cursor, such
as Mechanical Desktop’s “Ignore Z Coordinate” feature. When a conflict occurs, the application
that cannot gain cursor control displays an error message such as “Unable to Register Input
Point Filter.” If Raster Design’s Raster Snap interferes with a cursor control feature in another
application, you can turn off Raster Snap. If another application is interfering with Raster
Snap, consult that application's documentation for details on how to disable the conflicting
feature.

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 (page 187)

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 (page 203)

You can configure raster snapping and toggle it on and off on the Raster Snaps
tab of the Drafting Settings dialog box.