Rounded Rectangle¶

In one sentence: Draw an axis-aligned rectangle (or an oblong with rounded ends) in one step, with all four sides automatically added and the corners automatically constrained to be right angles.

Overview¶

Workbench: Sketcher · Menu: Sketch → Sketcher geometries → Rectangle
Toolbar: Sketcher Geometries (Rectangle dropdown) · Shortcut: G, R (default: Rectangle)

Three rectangle variants share one toolbar dropdown:

Tool	Shortcut	Description
Rectangle	`G, R`	Click two opposite corners
Centered Rectangle	`G, V`	Click the centre, then one corner
Rounded Rectangle	`G, O`	Click two opposite corners; a radius input sets the corner arcs

All three automatically add Right Angle constraints at the corners so the outline is always truly rectangular. You then add width, height, and position constraints to fully define the shape.

Intuition¶

Drawing a rectangle manually (four lines + four right-angle constraints + four coincident constraints at corners) is tedious. The Rectangle tools do all of that in two clicks, giving you a closed, properly constrained rectangle that only needs its width and height set.

Centered Rectangle is useful when you know where the middle of the rectangle should be (e.g. centred on a hole pattern) rather than a corner. Rounded Rectangle adds arc fillets at all four corners simultaneously, useful for rounded slots, panel cutouts, or organic outlines.

When to use it¶

You need any rectangular profile — plates, pads, pockets, slots.
The rectangle must be aligned with the sketch's X/Y axes (all tools here produce axis-aligned rectangles; for a rotated rectangle, draw lines and add angle constraints manually).
You want rounded corners from the start rather than adding fillets afterwards (Rounded Rectangle).

When NOT to use it¶

You need a rotated rectangle — draw four lines and apply angle + parallel constraints manually.
You need a rectangle that is part of a larger polyline — use Polyline to draw the sides one by one so you can continue the chain.
You need only the shape of a slot (two semicircles and two straight sides) — use Create Slot which creates a proper slotted profile.

Step-by-step walkthrough¶

Rectangle (corner-to-corner)¶

Press G, R or select Rectangle from the dropdown.
Click one corner of the rectangle.
Click the opposite corner. Four lines appear, corners are right-angle constrained, and all four sides are connected with coincident constraints.
Add width and height constraints using Dimension or Horizontal/Vertical Distance.
Fix the position — constrain one corner or the centre to the origin or a known point.

Centered Rectangle¶

Press G, V or select Centered Rectangle.
Click the desired centre point.
Click one corner. The rectangle is drawn symmetrically around the centre.
Constrain width, height, and centre position.

Tip

Centered Rectangle automatically centres the shape, but it does not add a symmetry constraint about the sketch origin. Add a Lock Position or Coincident to the centre point to fix it.

Rounded Rectangle (Oblong)¶

Press G, O or select Rounded Rectangle.
Click two opposite corners of the bounding box.
A dialog or input field requests the corner radius. Enter the radius value and confirm.
The rounded rectangle appears: four line sides with arc fillets at each corner.
Constrain width, height, corner radius, and position.

Parameters¶

Rectangle / Centered Rectangle¶

Parameter	Type	Applied via
Width	Distance	Horizontal Distance
Height	Distance	Vertical Distance
Position	Coordinate	Lock Position or Coincident on a corner or centre

Rounded Rectangle¶

All parameters above, plus:

Parameter	Type	Applied via
Corner radius	Distance	Radius/Diameter applied to any corner arc

Advanced usage¶

Constraining all four sides at once¶

After drawing a rectangle, you can select opposite sides and apply an Equal constraint to enforce that width equals height (making a square). Or select all four arcs in a Rounded Rectangle and apply Equal to ensure uniform corner radii.

Using the centre point of a Rectangle¶

A rectangle drawn with the plain Rectangle tool does not have an explicit centre point. To constrain the centre, add a Point at the intersection of its diagonals and use Coincident to connect it to the desired reference. Alternatively, use Centered Rectangle from the start.

Common mistakes and pitfalls¶

Rectangle is slightly off-axis (not perfectly horizontal/vertical)

Cause: The two corner clicks were not exactly aligned, producing a near-horizontal (but not quite) rectangle.
Fix: The right-angle constraints at corners ensure the angles are exactly 90°, but the rectangle can still be rotated as a whole. Add a Horizontal constraint to one side to lock it to the X-axis.

Cannot add a width constraint — already over-constrained

Cause: Both corner X-coordinates were already fixed by Lock Position constraints.
Fix: Remove one of the X-position constraints and replace it with the width constraint.

Python API¶

Minimal example¶

import FreeCAD as App
import Sketcher
import Part

doc = App.activeDocument()
sketch = doc.getObject("Sketch")

# Draw a 30 × 20 rectangle with bottom-left corner at origin
w, h = 30.0, 20.0
# Four corners
pts = [
    App.Vector(0, 0, 0), App.Vector(w, 0, 0),
    App.Vector(w, h, 0), App.Vector(0, h, 0)
]
# Four edges
ids = []
for i in range(4):
    ids.append(sketch.addGeometry(
        Part.LineSegment(pts[i], pts[(i+1) % 4]), False))

# Join corners
for i in range(4):
    sketch.addConstraint(Sketcher.Constraint(
        "Coincident", ids[i], 2, ids[(i+1) % 4], 1))

# Horizontal and vertical constraints
sketch.addConstraint(Sketcher.Constraint("Horizontal", ids[0]))
sketch.addConstraint(Sketcher.Constraint("Horizontal", ids[2]))
sketch.addConstraint(Sketcher.Constraint("Vertical",   ids[1]))
sketch.addConstraint(Sketcher.Constraint("Vertical",   ids[3]))

# Width and height
sketch.addConstraint(Sketcher.Constraint("Distance", ids[0], w))
sketch.addConstraint(Sketcher.Constraint("Distance", ids[1], h))

# Pin bottom-left corner to origin
sketch.addConstraint(Sketcher.Constraint("Coincident", ids[0], 1, -1, 1))

doc.recompute()