About Reference Planes

Reference planes help you manipulate objects and components precisely. For example, you can move one element (such as a point) along the Y axis of another element (such as a polygon).

The active plane specifies the reference frame used for transformations, as well as for drawing objects such as curves and polygons. Only one reference plane can be active at a time — you can choose one of the default reference planes or create your own. You can create transient, or temporary, reference planes as you work, or you can create permanent reference planes that are saved with the scene.

The cone translates along the X axis of the coordinate system defined by the reference plane (shown as a light grid).

You work with reference planes using the Ref and Plane buttons on the Transform panel. The main difference between the two is how the three mouse buttons work when not using the manipulators:

Ref is an XYZ mode like Global, Local, Par, and Obj.
Plane is a drag mode like View.

For details about transforming with Ref and Plane modes, see Transforming Elements with Reference Planes.

Reference planes are not relational. If you create a reference plane based on an object or component, and then move the object or component, the reference plane does not follow it.

Types of Reference Planes

There are three types of reference planes: default, transient, and permanent.

Default Reference Planes

The default reference planes include the major planes of the global coordinate system, as well as a View plane which depends on the 3D view.

Transient Reference Planes

As you work, you can create transient, or temporary, reference planes. Transient reference frames are not saved with the scene. There can be only one transient reference plane at a time; the current one is replaced as soon as you define a new one.

Permanent Reference Planes

Permanent reference planes let you use the same reference plane again at any time, even after saving and reopening the scene.

Reference Planes in the Explorer

All reference planes are listed in the explorer under the Application > Data node. To see them, make sure that the scope of the explorer is set to Application.

A	Scope must be set to Application to see reference planes in the explorer.
B	The List node under Reference Planes contains all reference planes.
C	The permanent reference planes are saved in the scene. They can be renamed
D	Transform is the last active transient reference plane.
E	View, XY, XZ, and YZ are the default reference planes.
F	The currently active reference plane is repeated outside List.

Reference Planes and Symmetry

You can use the axes of a reference plane for symmetry when drawing in Plane mode. For example, you can draw two curves or chains that are symmetric with respect to a reference plane of your choosing. Click Sym in the Transform panel to activate symmetry, and right-click Sym to specify a plane of symmetry.