Shapes

The shape tool adds geometric annotations to the canvas: flat polygons, 3D solids with automatic face shading, speech-balloon callouts, clouds, plain lines, arcs, and grouping brackets. Every shape is an annotation, so it lives above your structures, moves and resizes independently, and takes fills, strokes, and effects from the Shape Properties panel.

Activating the tool

Press U or click the shape button in the toolbar. The button’s flyout menu lists the full catalog; pick an entry to make it the active shape type. While the shape tool is active, number keys jump to common types: 1 rectangle, 2 ellipse, 3 line, 4 arc, 5 square bracket, 6 curly bracket, 7 round bracket.

Drawing gestures

Drag on empty canvas to size the shape from corner to corner.
Shift+drag constrains proportions, so rectangles become squares and ellipses become circles. Lines, arcs, and brackets ignore this constraint.
Alt+drag draws outward from the center instead of from a corner.
Click without dragging to place a shape at the default 60 by 60 size.

After you release, the new shape is selected and the app switches to the Select tool. Hold Alt while releasing to stay in the shape tool and draw several shapes in a row. If grid snap is on, the starting point snaps to the grid; clicks on an existing shape still select it instead.

The catalog

Basic 2D shapes. Rectangle, ellipse, triangle, right triangle, diamond, hexagon, star, parallelogram, chevron, cross/plus, and cloud. Use these for highlighting regions, building diagrams, or boxing reaction conditions.

Block arrows. The flyout also lists arrow block, double arrow, curved arrow, and U-turn arrow. These filled arrow polygons are covered in detail on the special arrows page.

3D shapes. Cube, cylinder, cone, sphere, and pyramid. Each one shades its faces automatically from the fill color: the top face is lightened and the side face darkened, so a single color choice produces a solid-looking object. The sphere instead renders with a radial gradient highlight. 3D shapes default to a gray fill when you draw them with fill set to none, since unfilled faces look broken.

Callouts. Callout, rounded callout, and oval callout are speech balloons with a pointer. Drag the gold handle on the bottom edge to slide the pointer’s base, and drag the handle at the pointer tip to aim it anywhere, including positions well outside the balloon body. Pair a callout with a text annotation for labels.

Lines and arcs. Plain line, curved line, S-curve, spline, and multi-segment line are headless versions of the corresponding arrow types, plus a circular arc whose start and end angles you drag directly.

Brackets. Square, curly, and round brackets, each available as a matched pair or a single left or right half, plus a polymer bracket that adds a subscript “n”. Use brackets to group repeating units, mark complexes, or enclose intermediates. Brackets also have a dedicated toolbar tool on the [ key.

Handles

Selecting a shape shows the standard selection box: corner and edge handles resize, and the rotate handle rotates in 15 degree steps (hold Shift for free rotation).

Parameterized shapes additionally show small gold diamond handles that adjust geometry rather than size:

Star: inner-point radius (how spiky it is)
Triangle: apex position
Parallelogram: skew amount
Chevron: notch depth
Cross: arm thickness
Cube: depth of the 3D offset
Cylinder: cap curvature
Cone and pyramid: apex position
Callouts: pointer base and pointer tip
Block arrows: shaft and head proportions
Arc: start and end angles

Drag a gold diamond to change just that parameter; the rest of the shape stays put. Double-clicking a gold diamond resets that parameter to its default.

Styling

With a shape selected, the Shape Properties panel docks on the right and controls:

Stroke: color, width, and dash pattern.
Fill: none, solid color, linear or radial gradient, or a hatch, crosshatch, or dot pattern, plus a fill opacity slider.
Corner radius for rectangles and rounded callouts.
Effects: a drop shadow (color, blur, offset, opacity) and an outer glow (color, blur, spread, opacity). Effects are available for every shape except the curved arrow block and U-turn arrow.

Gradient fills come with a full stop editor (add, remove, and reverse stops, plus an angle slider with direction presets), and pattern fills add foreground color, thickness, angle, and spacing controls; see the Shape Properties Panel for details.

Double-click any slider in the panel to reset it to its default value. To restyle several shapes at once, select them together with the Select tool before editing.