Arrow Beautification
A curved arrow dragged by hand often comes out lopsided. The cleanup commands reshape a selected arrow into a symmetric arc or S-curve and keep its endpoint attachments. Most actions live in the right-click context menu on an arrow; the two most common ones also appear as buttons in the Properties panel.
Context menu actions
Right-click an arrow with the Select tool to open its context menu. Which items appear depends on the arrow type. Reaction, retrosynthesis, and arc arrows are excluded from most of these because their geometry is rigid.
Beautify
Inspects the arrow’s current shape and applies the matching clean form: a symmetric arc, or a balanced S-curve if the arrow already reads as one (or if its two ends are anchored to opposite sides of their bonds). This is the general-purpose “fix my arrow” action and is also available as the Beautify button in the Properties panel.
Auto S-Curve
Forces the arrow into a symmetric S-curve with equal lobes on either side of the chord. Useful for mechanism arrows that pass between two groups, such as proton transfers. Very short arrows fall back to a plain arc, since an S-curve needs room to develop both lobes.
Auto Shape
Chooses arc or S-curve from the exit directions at the two endpoints, ignoring the drawn shape. If the attachments (lone pairs, bonds) point to opposite sides of the chord, you get an S-curve; otherwise an arc. Use it when the shape should follow from where the ends are attached.
Flip Curve
Mirrors the bow to the other side of the chord. With a single curved arrow selected, the F key does the same thing; without an arrow selected, F types fluorine instead.
Straighten
Strips all curvature, waypoints, and handles and converts the arrow to a straight arrow between its endpoints. Available for any curved arrow type.
Symmetrize
Makes an existing curve symmetric about the chord’s perpendicular bisector: an arc gets its apex at the midpoint, an S-curve gets its inflection at the midpoint. For multi-waypoint splines this redistributes the waypoints evenly along the chord, so irregular waypoint spacing is replaced. Shown for curved spline, quadratic, and cubic arrows.
Smooth Curve
Recomputes the spline handles so the curve flows smoothly through all waypoints. Appears for curved spline and multi-segment arrows that have waypoints. Interior tangents you have aligned by hand are preserved, so re-smoothing does not destroy manual tuning.
Align to Dots
For curved spline arrows attached to a lone pair or radical, realigns the endpoint handles so the curve leaves or enters along the dot’s direction. Use it when dragging the arrow body has twisted the tip away from its electron source.
Tip and point items
A few more items appear only when they apply:
- Reset Tip to Bond Midpoint: moves a bond-anchored tip back to the middle of its bond and clears its gap. Shown when a tip sits off the midpoint.
- Flip This Tip to Other Side: for curved spline arrows anchored to a bond, moves the tip nearest the click to the other side of its bond.
- Reset Head to Perpendicular: for curved spline arrows anchored to a label or annotation edge, clears a custom head angle on the tip nearest the click.
- Delete Point, Remove Bezier Handles, and Add Bezier Handles: shown when you right-click near a waypoint. Add Bezier Handles applies to multi-segment arrows.
The standard items (Cut, Copy, Paste, Duplicate, Delete, Flip Horizontal, Flip Vertical, Bring to Front, Send to Back, and the other order items) appear in the same menu.
Bow slider
Curved spline arrows show a Bow slider in the Properties panel (the docked panel on the right). It sets the bow height as a percentage of the arrow’s chord length, from 0 to 100% for arcs and 0 to 50% for S-curves, which visually saturate around 35 to 40%. The slider controls magnitude only; the curve stays on its current side of the chord. Use Flip Curve or F to switch sides.
Two related sliders appear in the same section: Curviness (after Smooth Curve has run) adjusts the smoothing tension, and Squeeze (S-curves only) compresses the lobes toward the chord for a tighter S.