ALNCUT-bgol (Cut Alignment Between Chainages)

Command Type: AutoLISP routine (works in AutoCAD, BricsCAD, ZWCAD and most AutoLISP-compatible CAD platforms)
Developed by: BGol Community, bgol.in

Inspired by the general concept of alignment-splitting utilities that combine chainage marking with physical polyline segmentation in road, rail, and channel design. This is an original, independently written routine, new file name, new command name, new source code, created so the CAD community has a free, editable, open-source alternative.

Overview

ACUT marks chainage points along a selected alignment polyline at a fixed interval, and at the same time physically splits the alignment into separate polyline pieces at those same chainage points, so each segment between chainages can be selected, plotted, exported, or processed independently.

How to Use

1. Load ALNCUT-bgol.lsp into your CAD session (drag-and-drop the file onto the drawing window, or use the APPLOAD command).
2. Type ACUT at the command line and press Enter.
3. Select the alignment polyline (LWPOLYLINE) to mark and cut.
4. Enter the chainage interval when prompted (defaults to 30 if left blank or invalid).
5. The routine walks the alignment at that interval, placing a chainage label (Ch. ) at each point on layer BGOL-ACUT-CH (yellow).
6. At the same time, it rebuilds the alignment as a set of independent polyline pieces, one per chainage interval, on layer BGOL-ACUT-PIECE (magenta), each individually selectable.

Why Use It

• Two steps in one, combines chainage marking and physical splitting into a single command run, instead of marking chainages first and then manually breaking the polyline at every point.
• Individually selectable pieces, every chainage-bound segment becomes its own polyline, ready for separate treatment, export, or editing.
• Organized output, chainage labels and cut pieces land on their own dedicated layers, kept clearly separate from the original alignment.

Where to Use It

• Breaking a long alignment into manageable segments for staged construction planning, segment-by-segment quantity takeoff, or handing off specific chainage ranges to different teams.
• Any road, rail, or channel alignment workflow needing both chainage labeling and physical segmentation in one step.

Notes

• The original alignment polyline is left untouched; new chainage labels and piece polylines are separate entities.
• Each piece is rebuilt from 10 sampled points along its chainage range using the alignment's own curve parameterization, so curved (bulge-containing) alignments are approximated smoothly.
• Chainage interval defaults to 30 drawing units if you press Enter without a value, or enter an invalid number.
• Source code is fully open, feel free to study, modify, and redistribute it under the same open, free-for-all spirit.

Credits

Developed and shared for the CAD community by BGol Community. Website: https://bgol.in/ Free and open-source, use it, modify it, share it, for personal or commercial work alike.