Create Point By Line Line Extension/TrimPoint by Line / Line Extension/Trim

(This functionality is available with the Computations module)
(Not available in LISCAD Lite)

Allows either or both of two lines to be extended or timmmed to their intersection(s) by moving existing points or creating new points. Also allows for new points to be created at the intersection(s) without extending or trimming the line(s). Optionally creates or moves the points on each line's segment grade.

To run this option, select the Create/Point command and the Method / Line/Line Extension/Trim command from the Computations task to display the relevant dialog box.

Any points created will be given the attributes currently defined via the Attributes/Point command. You should use that command to set the required attributes before creating any points.

Create Point by Line/Line Intersection dialog box

Item Used to
Point ID Key in the identifier of the next point to be created.
Line 1 Key in, or select the first line to be used.
Line 2 Key in, or select the second line to be used.
Extend/Trim Select this option to extend or trim the line to the intersection. Note that the line will not be trimmed unless "Move Point" is also selected. If "Extend/Trim" is not selected, a new point is created at the intersection but the line is not extended or trimmed.
Move Point Select this option to move the end point of the line segment (which is closest to the intersection) to the intersection. If this option is not selected, then a new point is instead created at the intersection.
Grade Select this option to have any points moved or created on the grade of the relevant line segment. If this option is not selected, then any new points are created without an elevation, and any moved points retain their original elevation.
OK Creates and/or moves points (graded or otherwise), and extends or trims lines, as per the selected options for each line.
Next Update the point identifier field to the next available identifier greater than the identifier currently shown.
Last Update the point identifier field to one greater than the highest identifier in the data base.
Close Closes the dialog box.


The elevation and contourable point attributes are determined by the computation, not by the point attributes dialog. E.g. If the intersection point is being assigned an elevation and is being inserted into a break line it will be flagged as contourable regardless of the currently set point attributes.

If you select a block that has a lot of parallel lines to the selected line 2, the system correctly repeats warnings about intersection points a long way away. You can use the provided 'Cancel' button to end the process.