Edit Mesh > Duplicate Face

Creates a new separate copy of any selected faces. The duplicated faces become part of the original mesh which otherwise remains unaffected.

Edit Mesh > Duplicate Face >

Separate duplicated faces: Separates faces automatically after they are duplicated. The duplicated faces are separated into their own separate object. Any pre-existing shells in the mesh will not be affected. This is the default setting.

If this option is turned off, you’re in component selection mode with all the duplicated faces selected.
Offset: Enter a value to offset the edges of the extruded, extracted, or duplicated faces.

This option can be used to produce a bevel effect for extrusions, cut-outs around faces using Extract, and to uniformly scale duplicated faces.

polyChipOff node

Additional modifications can be made to a duplicated face by editing the following attributes on the polyChipOff node using the Attribute Editor or Channel Box.

Translate: This value moves the extrusion or duplicated face locally along the X, Y, or Z axis. Positive or negative values indicate how far the extruded or duplicated faces are moved locally.
Rotate: This value sets the angle at which you want to rotate the extruded or duplicated faces locally around the X, Y, or Z-axis.
Scale: This value scales the extrusion or duplicated faces locally along the X, Y, or Z-axis.
Direction: Enter a value to set the location of the X, Y, or Z-point in the local axis. Notice how the manipulator handles change accordingly when you change the Y direction value to 4.0.

Global Values

Translate: This value moves the extruded or duplicated faces along the X, Y, or Z-axis.
Rotate: This value sets the angle by which you want to rotate the extruded or duplicated faces around the X, Y, or Z-axis.
Scale: Enter a value to scale the extrusion or duplicated faces along the X, Y, or Z-axis.

Other Values

Random: Enter a value to duplicate faces in random directions, with a value of 0 to 1. Lower values are closer to the specified direction. Higher values are more randomized.

In the following example, faces were extruded with random values of 0, 0.5, and 1.
Duplicate: Turn this attribute on to extract the faces instead of duplicating them.
World space: Turn on the World Space setting to use the world space coordinate system when you change values randomly.
Keep faces together: When this attribute is off, Maya duplicates each face separately. When this option is on, Maya duplicates the faces as a whole.