Use the same methods to modify a face, edge, or vertex that you use to modify the
entire object:

• Drag grips
• Use gizmos (3DMOVE, 3DROTATE, 3DSCALE)
• Enter object editing commands (MOVE, ROTATE, SCALE)

About Modifying Subobjects

When you move, rotate, or scale a subobject, the subobject is modified in a way that
maintains the integrity of the 3D solid or surface. For example, when you drag an
edge to move it, the adjacent faces are adjusted so that they remain adjacent to the
edge.

Several results are possible when you modify a solid or surface. When you move, rotate,
or scale subobjects, you can press Ctrl one or more times as you drag to cycle through
modification options.

The following illustration shows the modification options for moving a face.

Move, Rotate, and Scale Subobjects on Composite Solids

When you modify composite solids, the effect of the edits depends on the current setting
of the History property.

• To modify subobjects of each history component separately, the History property must
  be set to Record (On).
• To modify subobjects of the combined composite solid as a whole, the History property
  must be set to None (Off).

Rules and Limitations When Moving, Rotating, and Scaling Subobjects on 3D Solids

You can only move, rotate, and scale subobjects on 3D solids if the operation maintains
the integrity of the solid. The following rules and limitations apply to moving, rotating,
and scaling subobjects:

• When you use grips to modify subobjects, grips are not displayed on the subobjects
  that cannot be moved, rotated, or scaled.
• In most cases, you can move, rotate, and scale both planar and non-planar faces.
• You can only modify an edge that is a straight line and that has at least one planar
  adjacent face. The planes of the adjacent planar faces are adjusted to contain the
  modified edge.
• You cannot move, rotate, or scale edges (or their vertices) that are imprinted inside
  faces.
• You can only modify a vertex if it has at least one planar adjacent face. The planes
  of the adjacent planar faces are adjusted to contain the modified vertex.
• When you drag a subobject, the final result might be different than the preview displayed
  during the modification. This result occurs when the solid geometry is adjusted in
  order to maintain its topology. In some cases, the modification is not possible because
  it changes the topology of the solid too severely.
• If the modification causes spline surfaces to be extended, the operation is often
  unsuccessful.
• You cannot move, rotate, or scale non-manifold edges (edges that are shared by more
  than two faces) or non-manifold vertices. Also, if some non-manifold edges or vertices
  are present near faces, edges, and vertices that you modify, the operation might not
  be possible.