Planar

Toolbar	Menu	Alias	Status bar
Not on toolbars.	Not on menus.	P	Planar

Toolbar

Alias

Status bar

Not on toolbars.

Not on menus.

The Planar command limits successive picked locations to the same construction plane elevation as the previous location.

Planar mode aids in creating planar objects with commands that allow free picking. Successive points have the same construction plane elevation.

From the Curve menu, click Free-form, then click Control Points.
Pick the first point in the lower part of the Top viewport.
Move the cursor to the Front viewport and continue drawing.
You will see that all the points you pick define a planar curve at the same elevation in the Front viewport. (Watch the Top and Right viewports). That elevation for the Front viewport was defined by the very first point you placed in the Top viewport.
With Planar off, the subsequent points would be at elevation 0 in the Front viewport.

Each point picked in a viewport will have the same elevation from that viewport's construction plane as the previous point, regardless of where the previous point was picked.
Planar mode can be overridden with elevator mode or object snaps.

SetPlanar

Toolbar	Menu	Status bar
Not on toolbars.	Not on menus.	Planar > Planar Mode On/Off

Toolbar

Status bar

Not on toolbars.

Not on menus.

Planar Mode On/Off

The SetPlanar command turns Planar mode on, off, or toggles the current state.

Specify a command line option.
This is useful for inclusion in a script file for the ReadCommandFile command.