Design-rule check (DRC)

Verify → Design rules… opens a per-layer table of limits: min width, min spacing (both in µm) and min area (nm²). Leave a cell blank to skip that check. One-click writer presets set the min-width floor on every layer at once — laser (1.5 µm), e-beam (200 nm), or BEAM (500 nm).

Press F7 (or Verify → Run design-rule check) to run. Then:

• Every SRef / ARef in the active cell is expanded first, so a spacing error between two instances of the same cell is caught — it only exists in the parent, and checking the un-expanded cell would report clean.
• The check runs in a background worker with a Cancel button, and is strictly read-only: it never touches your drawing or the undo stack.
• Violations appear as numbered markers on the canvas. Press F2 / Shift+F2 to step through them; the view zooms to each one with enough surrounding geometry to see what went wrong. Verify → Clear violations removes them.

Rules are remembered in your browser and apply to whatever document you open — they describe the process you intend to fabricate with, not the drawing. They are not written into the .gds.

What is checked: boundaries and boxes. What is not: paths (Glyph tells you when a checked layer contained paths, rather than implying a clean result), enclosure/overlap between layers, and connectivity. Very dense layers are slow — the check is exact, not sampled.