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CLOCKFACE LISP: Draw a Longcase Clock, or Run It Live

August 6, 2026

CLOCKFACE draws a longcase — grandfather — clock: case, hood, dial, hour marks and pendulum, with the hands set to the current time or to any time you give.

What ClockFace does

Draw mode produces real geometry you can keep, plot and edit. A clock face is a genuine thing to put on a drawing: schools, stations, foyers.

Live mode is the original novelty — the clock runs on screen with a swinging pendulum, drawn as temporary vectors, until you press Escape. Nothing is added to the drawing.

How to use it

  1. Load the routine with APPLOAD, or put it on your support file search path.
  2. Type CLOCKFACE.
  3. Choose Draw or Live.
  4. For Draw, pick the insertion point and give a time, or accept the current one.
  5. For Live, press Escape to stop.

How it works

The case outline is a vector list carried over unchanged from 1986 — a sequence of triples, each a pen code and a coordinate, in a 1200-unit tall space. Code 3 lifts the pen and moves; code 4 draws to the point.

That is a plotter instruction stream, and it is preserved exactly. It is somebody’s drawing of a clock, and there is nothing to derive it from — you either keep it or you lose the shape.

What has changed is what happens to it. The runs between pen-ups are collected into polylines and drawn as real objects, instead of being flicked onto the screen as vectors that vanish at the next regeneration. The original ran in an unbounded loop with no exit but Escape, wrote to the screen menu area through GRTEXT — which has not existed for many releases — and produced no geometry at all. You had a picture until the next redraw and nothing to show for it.

Notes and limits

  • Draw mode gives you real polylines you can hatch, scale and plot.
  • Live mode adds nothing to the drawing and clears on Escape.
  • The case shape is a 1986 vector list, preserved exactly rather than redrawn.
  • One undo group in Draw mode; nothing to undo in Live.

Download and details

NameClockFace — draw a longcase clock, or run it live on screen
DownloadClockFace.lsp — 12.3 KB, plain AutoLISP source. Downloads directly; no zip to unpack.
TypeAutoCAD AutoLISP routine
CommandCLOCKFACE
Requiresnothing beyond a CAD platform with AutoLISP.
Source size12.3 KB, 289 lines
Error handlingYes — a *error* handler restores every system variable it changed, on cancel as well as on error.
UndoThe whole operation is wrapped in a single undo group, so one U reverses all of it.
CompatibilityAutoCAD (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.
AuthorYZ, August 2026
LicenceFree to use, supplied “as is” with no warranty.

References

  • CANNON LISP — the other one that draws itself and cleans up after
  • MOONPHASE LISP — another drawn-from-the-clock routine
  • More free AutoLISP routines on this site
  • Wisey’s Steel Shapes — free structural steel section drawing program

Filed Under: AutoLISP Routines

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