Extend Line to Boundary
Moves the end point of a line (or a polygon vertex) to where its segment meets another line — to
close a gap to a crest, a toe or a boundary.
Extend a line
- Click Extend Line to Boundary on the Modify toolbar. The status line reads “Extend
Line: Click near the ENDPOINT you want to extend”.
- Click near the end you want to move. The segment highlights in yellow as you hover.
- Click the boundary segment to extend to. It highlights in cyan, with a dashed green preview
and a target mark.
- The point moves to the crossing — “Extend Line: Done. Click another ENDPOINT to extend, or
Escape to exit.” The tool stays on.
How the crossing is found
- The point moves to where the two segments would cross if both carried on in a straight
line. If that crossing is short of the current end, the line gets shorter.
- In plan the point keeps its height. With a section plane
active, the crossing is worked out in that plane and the height changes.
- The boundary can be any visible, unlocked line or polygon edge — even another segment of the
same drawing.
- Parallel lines never cross: “Extend Line: Lines are parallel - no intersection exists.”
Other ways to use it
| Method |
Result |
| Right-click after picking the end |
Starts again — “Extend Line: Reset.” |
| Right-click twice quickly |
Ends the tool |
| Escape |
Ends the tool |
| Works in 3D |
Pick in either view |
Undo
Each extend is one Ctrl+Z step.