2D to 3D By Surface Model

This command converts a 2D polyline into a 3D polyline by calculating 3D polyline vertices at all the intersects of the 2D polyline with surface entities (contour polylines, triangulation lines) and by interpolating elevations from these intersections at the original vertices locations. An application for this command is to create breaklines. For example, a ridge breakline could be generated from contour lines by drawing a 2D polyline along the ridge and across the contours. Then this command could grab the contour line elevations along the polyline to make a ridge breakline.

In addition to using entities in the drawing, the 2D polyline can be converted to 3D using a surface model stored in triangulation (.flt or .tin) file. If you use a file, then you can also use the polyline's current elevation as a vertical offset from surface.

Prompts

By Screen Entities:
Source of surface model [File/<Screen>]? Type S for Screen
Select polylines to convert.
Select objects: select the polyline(s) to convert
Select surface 3DFaces, lines and polylines.
Select objects:  select the surface entities (contour polylines, breaklines, triangulation lines, etc)

Reading points ... 692

Keep existing polylines [Yes/<No>]? Press Enter
This command creates a new 3D polyline, and this prompt allows you to keep the old polyline.
Set layer name for converted polylines [Yes/<No>]? Press Enter
This allows you to assign the new polyline to a layer.
Converting polylines ...
Converted 1 polylines.

By a .flt or .tin File:
Source of surface model [<File>/Screen]? Type F for File
Select polylines to convert.
Select objects: select the surface entities (contour polylines, breaklines, triangulation lines, etc)

Use current polyline elevations as vertical offset from surface [Yes/<No>]? Press Enter
This will offset the new polyline by its current elevation. That is, if a polyline has an elevation of -4 and the surface you are converting it to has an elevation of 800, then saying Yes will drape the polyline at an elevation of 796.
Keep existing polylines [Yes/<No>]? Press Enter
This command creates a new 3D polyline, and this prompt allows you to keep the old polyline.
Set layer name for converted polylines [Yes/<No>]? Press Enter
This allows you to assign the new polyline to a layer.

Keyboard Command: 2dto3dp
Prerequisite: A polyline and surface lines or grid file or triangulation file.