3D Subtract

In this Task

• A new profile will be drawn on the side of the chair body.
• This circle will be modified, then extruded through the entire model.
• This extrusion will be used as a subtracting unit, creating a cut-out through the base of the chair.
• Material Properties will be added to the model.

Associated Tasks

• Using the Selector Shell handles to manipulate the shape of the circle.
• Extruding a profile through a part.

Before you Start

• View is set to Isometric South East. Workplane is set to Plane by World.
• Unlock the Model layer which was locked in the previous Task.

Take Note

• The circle is used as an extrusion profile only and does not have to connect to the surface through which it is being extruded, provided the circle is in the same plane as the extrusion. The circle is deleted after the extrusion is produced.
• The extrusion done in this task is not to any specific measurement. It must, however, exceed the overall width of the base of the chair.

3D Subtract

Ribbon : Modify | 3D Modifications | 3D Boolean Operations | 3D Add

Default Menu : Modify | Modify 3D Objects | 3D Boolean Operations | 3D Add

Modify > Modify 3D Objects > 3D Boolean Operations > 3D Subtract

This 3D Boolean function creates a new object by subtracting the volume of a secondary object from an intersecting primary unit.

In this task, a new extrusion will be created which will be used as a subtracting unit for the model, shown below.

WorkPlane by Facet

Ribbon : Workspace | Workplanes | WorkPlane | by Facet

Palette : 3D Model | Workplane | Workplane by Facet

Right click in the Editor | Workplane by Facet

This workplane feature applies a workplane to a selected facet (flat surface) of a 3D object.The Page Up and Page Down keys can be used to cycle between the available facets of the part.Workplanes can be placed onto a facet for single-instance applications using the Auto Workplane by Face tool.

 

Select the Workplane by Facet tool from the menu options above, then select the side facet shown below. Make sure the XYZ axes are all at 90° to each other.

Placing the Workplane on the side facet of the model

Turn the view to Front, then draw a circle onto the edge shown below, then use the stretch handles to stretch the left handle towards the left as shown in the illustration below.

Creating a new extrusion profile

Take Note

The circle is used as an extrusion profile only and does not have to connect to the surface through which it is being extruded, provided the circle is in the same plane as the extrusion. The circle is deleted after the extrusion is produced.

Simple Extrude

Ribbon : Draw | Draw 3D | Simple Extrude

Default Menu : Draw | 3D Object | 3D Profile Based | Simple Extrude

Palette : 3D Model | 3D Object | Simple Extrude

This extrusion tool sweeps a 2D profile in a plane perpendicular to the workplane to create a 3D object.

 

Make sure the Model layer is unlocked.

Turn the view to Isometric South East, then use the Simple Extrude tool to extrude the profile through the model. The extrusion length is not important, provided it exceeds the width of the model, shown below.

Extruding the profile to create an extrusion

From the Boolean Facet menu, select 3D Subtract. Select the Primary unit first (the combined objects which form the chair) then the Subtracting unit (the new extrusion.) The result is shown below left using the Suppress Hidden Line view. The view below right is shown rendered.

The circle profile which was used to create the extrusion can be deleted.

Result of creating the cut-away portion of the base