The CPlane command sets the origin and orientation of the construction plane in the active viewport.


Pick a new origin point or choose an option.

Command-line options


The construction planes in all viewports change so their origin is at the picked location.


The Curve option sets the construction plane perpendicular to a curve.

Curve steps

1. Select a curve to orient construction plane.
2. Drag the construction plane's new x and y axes to a new location.


Use the Curve option to quickly position your construction plane at various stations along a central rail curve as preparation for doing a one rail sweep, for example. Once your construction plane is positioned, you can use drawing tools to draw a cross-section curve in the 3 D location where it needs to be. This direct drawing method can be quicker and more convenient than drawing the curve on a world plane and then trying to move and rotate it into place in 3-D.
The direction of the curve affects the direction of the axes. If the construction plane does not go the direction you want, flip the direction of the curve with the Flip or Dir commands.


The Elevation option changes the elevation (z-direction) of the construction plane.

Elevation steps

Pick a new elevation.

Or, type a distance to move the origin from its previous location.


Positive numbers move the construction plane up along the positive z-axis.
Negative numbers move the construction plane down.


The Object option sets the construction plane in the active viewport to an object.

Object steps

Select a curve or surface.

The origin and tangency of the new construction plane is based on the "midpoint" of the untrimmed version of the surface.


The Rotate option rotates the construction plane.

Rotate steps

1. Pick the start of the rotation axis.
2. Pick the end of the rotation axis.
3. Type the angle to rotate the construction plane.

Or, pick two points to specify the angle.


The Surface option sets the construction plane to match a surface. The placement is constrained so that the construction plane is tangent to the surface.

Surface steps

1. Select a surface.
2. Pick an origin or press Enter.
3. Pick an x-axis direction or press Enter.

Surface options


The Flip option reverses the direction.


The IgnoreTrims option uses entire untrimmed underlying surface.


The Through option moves the construction plane origin to a selected point.

Through steps

Pick a location to move the origin to.

Through option


The All option resets all construction planes to the new origin.


The View option sets the construction plane in the active viewport parallel to the view.

View steps

Click View or type V.


The World option restores the specified default construction plane.

World steps

Specify an option.

World options








The 3Point option sets the construction plane in the active viewport by specifying points to establish the x-, y-, and z-directions.

3Point steps

1. Pick a new origin, or press Enter.
2. Pick the x-axis.
3. Pick the y-axis.

3Point options


The Vertical option sets the construction plane perpendicular to the current construction plane.


The ZAxis option sets the construction plane z-axis direction.


The Undo option restores the previously used construction plane in the current viewport.

Undo steps

Click Undo or type U.


Shift + Home


The Redo option restores the construction plane that was active before the Undo option was used.

Redo steps

Click Redo or type D.


Shift + End


The CopyCPlaneToAll command changes all viewports to have the same construction planes as the specified viewport.


The CopyCPlaneSettingsToAll command changes all viewports to have the same grid settings and snap spacing as the specified viewport.

See also

Use construction planes


Set up a relationship between a construction plane and an object.


Manage the named construction planes list.

Rhinoceros 5 © 2010-2015 Robert McNeel & Associates. 17-Sep-2015