Following Polylines

The polyline follower tools can trace bitonal raster polylines and convert them to AutoCAD polyline entities or contours.

Separate tools are available for vectorizing 2D polylines, contour lines, and 3D polylines.

Follower tools trace or follow the selected polyline, pausing for input at any decision point where the follower can no longer proceed on its own. Decision points occur when the follower meets confusing geometry or reaches the end of a raster line. You can also use settings in the Raster Design Options dialog box to instruct the follower to stop at raster intersections.

The follower traces the polyline in both directions from the point you clicked, and always presents you with two decision points at the same time. If the current decision point is not on screen, AutoCAD Raster Design toolset automatically pans to it. At each decision point, you can take one of the following actions:

• Manually add points. This is useful, for instance, to cross the gaps in dimension lines created for labels.
• Switch to the other decision point.
• Backup to the last vertex.
• Rollback to a previous vertex that you select with the pointer.
• Specify a direction for the follower to take. This option is useful when the follower pauses at a “T” intersection.

Note: When you use the Direction option, it becomes the default option until another option is used or until the polyline is completed.

• Continue in the direction that seems most apparent to the follower. This option is useful when the follower has simply paused at a raster intersection.
• Follow a vector entity. This option is useful for following portions of an image that have already been vectorized.
• Close the polyline by drawing a single segment between the two decision points.
• Join the current polyline to an existing vector polyline.
• Cancel the current polyline and begin again by pressing Esc.

Note: To make the most efficient use of the Polyline Follower, you should adjust the settings on the VTools Follower tab on the Raster Design Options dialog box.

Vector Separation Options

You can use these options to automatically manage layers, linetypes, and polyline widths for lines created by vectorization tools. Specify a range of line widths for the raster entity on the General tab of the Vector Separation Options dialog box, then assign layer and polyline width values to these ranges. When a vectorization command is executed, AutoCAD Raster Design toolset examines the raster line width and assigns the values you specified for that width to the newly created polylines. You can access the Vector Separation Options dialog box by clicking the Vector Separation button on the VTools General tab of the Raster Design Options dialog box. For more information, see General Vector Separation Options.