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draw pen

Blossom Merz edited this page Oct 19, 2026 · 1 revision

Home > Draw > Pen

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Modeling Menus

Pen (tool)

Draw a spline by placing anchors, and insert anchors into one that is already there.

Menu: Draw > Pen | In depth: Splines

Important

Under construction. The Pen is new and this page describes work in progress. Nothing here is a promise about the finished feature.

Drawing one

Four rows, one Pen gesture each. First, a click places a square corner anchor and the span to it runs straight. Second, a drag pulls out a round smooth anchor whose two handles open symmetrically, with an arrow along the drag. Third, an existing span runs from a triangular first point to a smooth end anchor with a long handle; a click partway along it inserts a new anchor there, which carries its own handles. Fourth, the same span with shift held: the anchor lands at the top of the arch instead, on a dashed line marked Y max.

  • Click places a corner anchor.
  • Click and drag pulls out a smooth anchor, its two handles opening symmetrically as you drag.
  • Click the first anchor to close the spline. It takes more than two anchors to close, since two would double back on themselves.
  • Escape finishes the spline open.

A spline of one anchor is not kept. If you place a single anchor and finish, the click is treated as one you changed your mind about and nothing is left behind.

Shift while placing constrains the direction from the previous anchor, the same as it does everywhere else in Locus. The anchor also lands on geometry that the locked direction runs into near the cursor, so a constrained span ends on the line it meets rather than a hair off it.

Inserting into a spline that exists

Hover an existing spline with the Pen and a dot appears on the curve, with the span under it picked out. That is where the anchor would go.

  • Click the span to insert an anchor there. The curve does not move. The new anchor is selected and the spline is left open for editing.
  • Shift-click the span inserts at the nearest X or Y maximum of that span instead. An anchor there is what makes a shape's bounding box tight and its outline predictable under offset and export. On a straight span, or a curve with no interior extreme, it falls back to the cursor.

The hint only lights up on a spline the Pen can actually insert into, so a locked object, or an import that has not been converted, will not offer one.

Snapping

Anchors snap to the same things everything else does: construction points, crossings, guides, alignment lines, and the anchors of other splines. The position is worked out from where you clicked rather than from where you hovered.

Related

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