To Create a 3D Polyline

1. Click Raster menu Vectorization Tools3D Polyline Follower.

   The following prompt appears:

   Specify first fence point or [follow Vector]:

2. Do one of the following:
   • Click several points to define a polyline fence that intersects several contours.
   • Enter v (Follow Vector) and press enter, then select an existing vector polyline for the follower to use.
   Tip: If you have already vectorized a contour, use OSNAP to snap a polyline vertex to that contour. AutoCAD Raster Design toolset uses its elevation as the default when the follower pauses at that vertex.

   The following prompt appears:

   Specify elevation, press Enter to accept or [Interpolate/Existing/Undo/Skip/iNsert/Move]:

3. Do one of the following:
   • Enter an elevation, then press Enter.
   • Press Enter to accept the current elevation value.
   • Enter i (Interpolate) to interpolate the value based on the previous elevation and the next elevation.
   • Enter e (Existing), then click a vector entity from which to copy the elevation.
   • Enter u (Undo) to undo the last elevation entered.
   • Enter s (Skip) to skip the current raster impact point.
   • Enter n (Insert), then click a point to insert another vertex for the polyline.
   • Enter m (Move), then click a point to move the current vertex.
4. Repeat step 3, or press Enter to exit the command.

Note: When following an existing polyline, the 3D Polyline follower considers the end nearest the point you picked as the start point, regardless of the original start or endpoint for the polyline.

Tip: Use raster snapping to make it easier to pick points on the raster entity you are converting. For more information, see Raster Snapping.