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Rotate / Polar Transform

In one sentence: Rotate selected sketch geometry about a centre point, or create a polar (circular) array of copies evenly distributed around that centre.

Overview

Workbench: Sketcher · Menu: Sketch → Sketcher tools → Rotate / Polar Transform
Toolbar: Sketcher Tools · Shortcut: none

The Rotate tool moves geometry through an angle about a specified centre point. With more than one copy specified, it creates a polar array — copies placed at equal angular intervals around the centre, like spokes on a wheel.

Intuition

Think of a clock face: if you draw one clock hand and use Rotate with 12 copies and 30° per step, you get a full set of hour markers evenly spaced around the centre. Rotate / Polar Transform is that circular repetition tool.

When to use it

  • Placing bolt holes evenly around a bolt circle (polar array).
  • Rotating a cam profile or tooth to a specific angular position.
  • Creating a fan blade or radial fin pattern.
  • Rotating one sketch element to align it to a non-axis angle.

When NOT to use it

Step-by-step walkthrough

  1. Select the geometry to rotate or copy.
  2. Activate Rotate / Polar Transform from the toolbar or menu.
  3. Click the rotation centre point in the viewport.
  4. In the task panel:
    • Number of copies: 0 for a pure rotation; N for N additional copies.
    • Total angle: the full angular span of the array, or just the rotation angle for a single rotation.
    • Step angle: angle between consecutive copies (= total angle / N).
  5. Click OK.

Tip

For a full circle array, set Total angle = 360° and Number of copies to the number of features − 1 (the original counts as 1, so for 6 holes set copies = 5).

Parameters

Parameter Type Default Description
Number of copies Integer ≥ 0 0 Extra copies. 0 = rotate geometry in place.
Total angle Degrees 360° Angular span of the full array.
Step angle Degrees Computed Angle between consecutive copies.
Centre point 2-D coordinate Interactive click The pivot of the rotation.
Clone Toggle Off If on, copies are Clones with constraints linked to original.

Common mistakes and pitfalls

Polar array does not close evenly

Cause: The total angle (360°) is not evenly divisible by the step angle, leaving a gap before the last copy re-meets the first.
Fix: Set the total angle to exactly 360° and let the step angle be computed as 360° / (copies + 1).

Centre point snaps to wrong location

Cause: The centre point click landed on a nearby vertex rather than the intended centre.
Fix: Place a Point at the intended centre and use Lock Position to fix it before running Rotate.

Python API

# Rotate is GUI-only; the underlying method may be:
# sketch.addPolarArray(geoIds, centre, angle, copies, clone)
# TODO: verify against Sketcher source.
print("Use the Rotate / Polar Transform tool interactively.")

See also