How to use the Polar Pattern tool in the Part Design Workbench

Contents

  • 00:00 Introduction
  • 00:47 360 degree rotation on a flat surface
  • 03:00 360 degree rotation around round body
  • 04:27 Flat sided box
  • 05:44 Partial rotation with Reverse option
  • 07:06 Limitation - Must use additive or subtractive features
  • 07:20 Limitation - Cannot create multiple solids
  • 07:32 Limitation - Cannot use complex shapes like fillets
  • 09:22 Final thoughts

The Polar Pattern Tool takes a feature and rotates one or more copies around the origin. It is part of FreeCAD's Part Design Workbench.

You can use the Polar Pattern Tool to create one or more copies of a feature in a circular arc. Examples of this include the holes wheel mounting bolts on a car wheel, or the mounting holes on a router base plate designed to support multiple routers. These are examples of features that are pockets or holes, but it can also be used with features that are extrusions. An example of this is a motor vehicle wheel hub that has the wheel mounting studs arranged in a circular pattern.

The Polar Pattern Tool creates a specified number of copies of the feature around an arc whose radius is defined as the distance from the centre of the feature to the origin. The arc covered by the resulting polar pattern can be up to 360o. Each copy of the feature is equally spaced around the polar pattern.

Important

The angle of rotation used to create the polar pattern starts at the centre of the selected feature. This is effectively ZERO degrees and the polar pattern rotates to the left or right depending upon the Reverse direction option.

Available Options

  • Axis: This option specifies the axis around which the polar pattern is created.

  • Angle: This option specifies the angle of rotation of the polar pattern. For example, a polar pattern with an angle of 90o would cover 1/4 of a circle. Similarly, an angle of 270o would cover 3/4 of a circle.

  • Reverse direction: This option allows you to control which direction the arc of the polar pattern is created. This option allows you to select the type of hollow you'd like to create. The options are:

    Important

    The Reverse direction option is only applicable when the angle is not 360o. You can set it when the angle is 3600 but you won't be able to see a difference because the features are placed in the same location regardless of how this is set.

  • Occurrences: This option specifies the number of times the feature is copied around the polar pattern.

Limitations

  • The Polar Pattern Tool does not allow you to create multiple solids. This is a limitation of the Part Design Workbench that affects all tools.

  • The Polar Pattern Tool only allows you to select Additive (e.g. extrusions, etc.) or Subtractive (e.g. pockets, holes, etc.) features. It does not allow you to select complex features such as boolean operations.

  • The Polar Pattern Tool does not allow you to use complex shapes such as fillets. When you select a feature that contains a fillet the Polar Pattern Tool attempts to create a polar pattern but eventually gives up.

    NOTE: It is unclear whether this is a failure within the Polar Pattern Tool itself, or whether it is in the underlying CAD engine that is used by FreeCAD.