Construction Geometry

In order to make more complex shapes in Part design (e.g. Hexagon, triangles, etc.), or using features such as mirror, you may need to use construction geometry. To use construction geometry, click on the button in the “Sketch Tools” toolbar; this toolbar is specific to the sketch workbench. When the button is not highlighted, it means that any element created will be standard geometry.

Sketch Tools

When the button is highlighted orange, it means that any element created will be construction geometry.


You can constrain standard elements to construction geometry in order to make specific shapes. The appearance of the feature will also indicate if the object is a construction or standard element. When sketching, if the element is made of grey dashed lines, then it is an unconstrained construction geometry. If it is made of green dashed lines, then it is constrained. Geometry with solid outlines are standard elements.


Another way of recognising construction geometry is that when you exit the Sketch Workbench the construction geometry will no longer be visible.





As you become more confident with design, you will begin to use construction geometry more and more. Below is an example of an impeller created using construction geometry. The first image shows all of the construction geometry used to create the half profile;

Construction geometry impeller 1

This profile was revolved 360 degrees using the shaft tool to create the following shape;


impeller body 1


The blades were then sketched using more construction geometry;

blades geometry


The finished project looked like this;


impeller complete


As you can see, construction geometry enables you to create complex shapes. Have a go at creating your own complex shapes!