Primitives Dialog¶

In one sentence: A single dialog that provides access to all the less-common parametric primitive shapes: Plane, Helix, Spiral, Circle, Ellipse, Wedge, Vertex, Line, and Regular Polygon.

Overview¶

Workbench: Part · Menu: Part → Primitives → Create Primitives…
Toolbar: Part Primitives · Shortcut: none

The Primitives dialog is a unified creation interface for shapes that do not have their own toolbar button. Select the desired shape from the dropdown, fill in the parameters, and click Create.

Intuition¶

Shapes like helices, spirals, and ellipses appear less often than boxes and cylinders, so they are grouped behind a single dialog rather than cluttering the toolbar. The dialog allows you to tweak parameters before creating the shape, unlike the direct primitive buttons which create at defaults and let you edit afterward.

Available shapes¶

Shape	What it creates
Plane	Flat rectangular face (not a solid)
Box	Rectangular box (also available directly)
Cylinder	Right cylinder (also available directly)
Cone	Cone or frustum (also available directly)
Sphere	Sphere or segment (also available directly)
Ellipsoid	Oblate or prolate ellipsoid
Torus	Ring shape (also available directly)
Prism	Regular-polygon prism
Wedge	Trapezoidal box — different top and bottom rectangles
Helix	3-D coil along the Z axis
Spiral	2-D expanding spiral in the XY plane
Circle	2-D circular edge (wire)
Ellipse	2-D elliptical edge
Point (Vertex)	Single vertex point
Line	Straight edge between two points
Regular Polygon	2-D regular polygon wire

Shape details¶

Plane¶

A flat rectangular face. Useful as a construction surface or as the base for a Ruled Surface or as a cutting plane for Section.

Parameter	Description
Length	X extent
Width	Y extent

Wedge¶

A trapezoidal prism with independent bottom and top rectangle dimensions. Good for ramps, gussets, and dovetail-like profiles.

Parameter	Description
Xmin, Ymin, Zmin	Corner of the base rectangle
Xmax, Ymax, Zmax	Corner of the top rectangle
X2min, Z2min, X2max, Z2max	Top face extent (the "small" rectangle)

Helix¶

A 3-D coil used as a sweep spine for springs, threads, and spiral features.

Parameter	Description
Pitch	Distance between successive turns (mm)
Height	Total axial length of the helix
Radius	Coil radius
Angle	Taper half-angle (0° = cylindrical helix, >0° = conical helix)
Left-handed	Handedness toggle

Spiral¶

A 2-D Archimedean spiral in the XY plane. Useful as a sweep path for watchspring or volute shapes.

Parameter	Description
Growth	Radial distance gained per revolution
Turns	Number of full revolutions
Radius	Starting radius

Circle¶

A 2-D circle edge (wire), not a solid. Use as a sweep profile or for Section operations.

Parameter	Description
Radius	Circle radius
Angle1	Start angle
Angle2	End angle

Ellipse¶

A 2-D ellipse edge.

Parameter	Description
MajorRadius	Semi-major axis
MinorRadius	Semi-minor axis
Angle1, Angle2	Arc extents

Regular Polygon¶

A 2-D closed wire of N equal sides.

Parameter	Description
Polygon	Number of sides (3 = triangle, 6 = hexagon, …)
Circumradius	Radius of the circumscribed circle

Step-by-step walkthrough¶

Creating a helix for a spring sweep¶

Part → Primitives → Create Primitives…
Select Helix from the dropdown.
Set Pitch = 5 mm (turn spacing), Height = 50 mm, Radius = 10 mm.
Click Create, then Close.
Select the Helix. Then run Sweep with a circular profile to create a spring solid.

Creating a wedge (ramp)¶

Open the Primitives dialog.
Select Wedge.
Adjust Xmin/Xmax for the base, X2min/X2max for the top (narrower creates a ramp).
Click Create.

Common mistakes and pitfalls¶

Circle and Ellipse produce edges, not faces

A Part Circle creates a wire, not a solid or face. Use Face from Wires to turn it into a face, or use it directly as a sweep profile.

Helix has no built-in solid — it is a sweep path

To make a spring, create a Helix and then use Sweep with a circle as the profile.

Python API¶

import FreeCAD as App
import Part

doc = App.newDocument()

# Helix (spring path)
helix = doc.addObject("Part::Helix", "SpringPath")
helix.Pitch  = 5.0    # mm per revolution
helix.Height = 50.0   # mm total
helix.Radius = 10.0   # mm coil radius
doc.recompute()

# Wedge
wedge = doc.addObject("Part::Wedge", "Ramp")
wedge.Xmin  = 0.0
wedge.Ymin  = 0.0
wedge.Zmin  = 0.0
wedge.Xmax  = 20.0
wedge.Ymax  = 10.0
wedge.Zmax  = 30.0
wedge.X2min = 5.0     # top face starts at X=5
wedge.Z2min = 0.0
wedge.X2max = 15.0    # top face ends at X=15
wedge.Z2max = 30.0
doc.recompute()

# Regular polygon (hexagon wire)
poly = doc.addObject("Part::RegularPolygon", "Hex")
poly.Polygon       = 6      # 6 sides
poly.Circumradius  = 10.0   # mm
doc.recompute()