Autodesk 00126-050008-1640A User Guide - Page 174

12 Tracing But if you know that the raster line has another form, using the drawLine option you can draw the missing parts, as the figure illustrates. 4. Repeat step 3 until you complete tracing a raster line. To correct a mistake use the Backstep and backSegment options. The first option cancels generation of all polyline segments obtained at the last tracing step, and the second option enables to cancel generation of polyline segments, obtained during polyline tracing. You can apply these options several times to cancel any number of steps or segments. WiseImage automatically stops tracing a polyline, if the latest created polyline segment crosses any other segment of the same polyline, or if the latest segment vertex is located close to the first vertex of the same polyline. In the latter case a closed polyline is created, and tracing is completed. 5. To stop tracing press ENTER. When tracing polylines with autodetection of direction, on reaching a node, the program tries to determine the trace direction, and draws a mark on the suggested raster line extension (AutoCAD-style cross of the current color), and the following prompt appears in the command line: [Direction/Backstep/backSegment/drawLine/pan2Center/Redraw/eXit/caNcel]: Pressing Enter accepts the tracing direction, suggested by the program. You can also select another tracing direction by specifying a point on the required part of the raster line. You must make a choice of direction in the given time period. This interval is set by the Pause parameter in the Trace tab of Conversion Options dialog. If the program fails to determine a direction automatically, then you will be prompted to indicate a direction manually, and once selected, tracing will continue operating in the automatic detection mode. Tracing Raster Symbols The Symbol method allows you to trace by picking raster objects similar to previously defined samples. * The procedure of symbol recognition is described in the section "Tuning Symbol Recognition Template Library" on page 214. 179