UNITSPAN measures between two points and shows the result simultaneously in decimal, fractional, engineering, architectural and metric notation — and does the same for the X and Y components and the bearing.
What UnitSpan does
DIST answers in whatever format UNITS happens to be set to. That is fine until you are reading an architectural drawing while filling in a supplier’s form that wants millimetres, or checking a fractional dimension against a decimal one.
This puts all of them on screen at once, so there is no converting in your head and no changing UNITS back and forth.
Nothing is drawn. The routine creates no geometry, no layers and no text, and leaves the drawing exactly as it found it.
How to use it
- Load the routine with
APPLOAD, or put it on your support file search path. - Type
UNITSPAN. - Pick two points.
- Set whether the drawing is in inches or millimetres.
- Read every format at once, and press Measure Again for the next one.
How it works
The raw distance is stored, plus the pure horizontal and pure vertical components, worked out by building two corner points from the X of one pick and the Y of the other.
Every value is normalised to inches internally, whatever the drawing is actually drawn in. That one decision is what makes the rest simple: the four imperial formats read the internal number directly, and the metric column is that number × 25.4. Tell the dialog the drawing’s unit basis and it divides on the way in accordingly.
Each row has its own precision slider, from 0 to 8 places, and the whole table redraws the instant you move one. Precision choices and the unit basis are remembered for the rest of the drawing session.
Results sit in edit boxes rather than plain text, so you can select a value and copy it straight out with Ctrl+C into an email or a form. Nothing you type into them affects the drawing — they are display only.
Measure Again re-picks two points without closing, so checking a run of dimensions is pick-pick-read, pick-pick-read.
Notes and limits
- Nothing is drawn and nothing is changed.
- Values are copyable straight out of the dialog.
- Precision is per row, 0 to 8 places.
- Tell it the drawing’s unit basis once per session.
Download and details
| Name | UnitSpan — measure once and read it in every unit format at once |
| Download | UnitSpan.lsp — 16.4 KB, plain AutoLISP source. Downloads directly; no zip to unpack. |
| Type | AutoCAD AutoLISP routine |
| Command | UNITSPAN |
| Requires | nothing extra — the dialog is written to a temporary file at run time and deleted again, so there is no .dcl to install. |
| Source size | 16.4 KB, 382 lines |
| Error handling | Yes — a *error* handler restores every system variable it changed, on cancel as well as on error. |
| Undo | Not needed — this routine only reads the drawing and changes nothing. |
| Compatibility | AutoCAD (any release with AutoLISP), BricsCAD, ZWCAD, GstarCAD, ProgeCAD and other IntelliCAD-based platforms. AutoCAD LT needs a LISP enabler. No .NET, no ObjectARX, no installer. |
| Author | YZ, August 2026 |
| Licence | Free to use, supplied “as is” with no warranty. |
References
- TAPEMEASURE LISP — measuring a run of segments rather than one span
- QUICKSPAN LISP — a quick span read-out with no dialog
- Metric units in CAD — which unit to draw in, and why it matters
- More free AutoLISP routines on this site
- Wisey’s Steel Shapes — free structural steel section drawing program