ELEVCOUNT-bgol (Interpolate N Intermediate Elevations)

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 count-driven elevation interpolation used in survey and profile 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

ELVN lets you specify exactly how many intermediate elevation values to generate between two known elevation labels, a count, not a distance. The routine linearly interpolates that many evenly-spaced values and places a text label for each, giving direct control when the number of points is dictated by layout or design requirements rather than a fixed interval.

How to Use

1. Load ELEVCOUNT-bgol.lsp into your CAD session (drag-and-drop the file onto the drawing window, or use the APPLOAD command).
2. Type ELVN at the command line and press Enter.
3. Select the first (start) elevation TEXT entity.
4. Select the second (end) elevation TEXT entity.
5. Enter how many intermediate levels to generate.
6. That many evenly-spaced elevation labels are created along the straight line between the two references, on layer BGOL-ELVN.

Why Use It

• Direct control, you decide exactly how many labels are produced, convenient when the count is dictated by the drawing layout rather than a spacing rule.
• No manual math, removes manual interpolation arithmetic, especially useful when the exact real-world interval isn't fixed.
• Consistent results, evenly-spaced output every time, reducing risk of arithmetic error when interpolating by hand.

Where to Use It

• Filling in a specific number of intermediate spot-elevations between two known survey/design levels when the exact spacing isn't fixed by a standard interval.
• Any land-survey or design drafting task needing a controlled, even split of elevation values between two reference points.

Notes

• Interpolated points are placed along the straight line connecting the two reference text insertion points, splitting the span into N + 1 equal segments.
• Text height for the new labels matches the first reference text's height (falls back to 2.5 if unavailable).
• Values are formatted to 2 decimal places, matching common survey precision conventions.
• 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.