HPGL/PLT Viewer

See what a plotter file will actually draw

HPGL and HPGL-2 files are plain text instructions for a pen plotter or vinyl cutter — a sequence of PU, PD, PA and similar two-letter commands — but they are not something you can eyeball. This tool parses the file and draws it as an SVG, right in your browser, so you can check a job before it reaches the machine.

What it reads

• PU/PD — pen-up travel moves and pen-down drawing moves, in both absolute (PA) and relative (PR) coordinate modes.
• SP — pen selection. Every pen number gets its own colour in the preview, so a multi-pen or multi-tool job is easy to read at a glance.
• CI — circles, and AA/AR — arcs with an absolute or relative center, both flattened into smooth curves.
• Anything else the file uses is still counted, and listed if it is not one of the mnemonics this tool draws, so you know exactly what was and was not rendered.

Units

HPGL plotter units are a fixed 1/40 mm (equivalently 1/1016 inch) — this never varies between files, so the preview's millimetre measurements and total plotted length are exact, not estimates.

What you get

• A scaled preview with every pen's strokes in its own colour.
• The number of pens used, the number of pen-down segments, the count of arcs and circles, the total plotted path length, and the overall drawing size in millimetres.
• A plain warning if the file contains commands this viewer does not draw, so you are never shown an incomplete picture without knowing it.

Typical uses

Check a file exported from a CAD/CAM or sign-cutting package before sending it to a plotter or cutter, inspect an old .plt archive you can no longer open on the original hardware, or compare two exports to see if a pen assignment changed. Nothing leaves your device — the file is parsed and drawn entirely client-side.