NODEBLK-bgol (Insert Block at Line Endpoints / Intersections)

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 automatic junction/node marking used in utility and drainage network drafting. 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

IBNP inserts a chosen block at the endpoints, intersections, or both, of a set of selected lines and polylines, a fast way to mark "nodes" or "junctions" in drainage, road, or pipeline network drawings.

How to Use

1. Load NODEBLK-bgol.lsp into your CAD session (drag-and-drop the file onto the drawing window, or use the APPLOAD command).
2. Type IBNP at the command line and press Enter.
3. Choose a marking mode at the prompt: Intersections, Endpoints, or Both (the default).
4. Select the lines/polylines to process, then press Enter to finish selection.
5. Type the name of the block to insert when prompted.
6. The routine detects the relevant junction points (per the chosen mode) among the selected entities and inserts a copy of the block at each one, on a dedicated layer, BGOL-IBNP (colour red). Coincident points (e.g. an endpoint that is also an intersection) are only marked once.

Why Use It

• Flexible targeting, choice of endpoints only, intersections only, or both, adapting to different marking needs in a single command.
• Time savings, automates finding and marking every junction across potentially many lines, instead of manually snapping and inserting blocks one at a time.
• Consistency, ensures every junction of the selected network is marked uniformly with the same block.

Where to Use It

• Road, railway, irrigation, or pipeline network drawings, where junction points need to be clearly marked for design reporting.
• Urban development and waterway/drainage projects where node or junction identification (e.g., manholes, chambers, connection points) is a core deliverable.
• Any network-style drawing (utility lines, drainage layouts) needing automatic junction/node markers before further labeling or reporting.

Notes

• Intersections are computed pairwise between all selected entities; supports LINE, LWPOLYLINE and ARC entities.
• Endpoints are read from each entity's curve start/end point, so it works consistently across the supported entity types.
• Block scale and rotation default to 1/1/0; edit *bgol-ibnp-scale* and *bgol-ibnp-rot* near the top of the .lsp file to change the defaults.
• Coincident-point tolerance defaults to *bgol-ibnp-tol* = 0.001 drawing units; adjust if your drawing uses a different precision.
• 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.