8

644 Chapter 8: Modifiers
Removing one edge is like mak i n g it invisible. The mesh is
affected only when you remove all but one of the edges
depending on o ne vertex. At that point, the vertex itself is
deleted a nd the surface is retriangulated.
To delete the associated vertices as well,
press and hold CTRL while executing a
Remove operation, either by mouse or with the
BACKSPACE key. This option, ca l led Clean
Remove, ensures that the remaining p olygons are
planar.
Left: The original edge selec tion
Center: Standard Remove operation leaves extra vertices.
Right: Clean Remove with CTRL+Re move deletes the extra
vertices.
Edges with the same polygon on both sides usually
can’t be removed.
Wa rni ng: Use of Remove can result in mesh shape
changes and non-planar polygons.
Split—
Divides the mesh along the selec ted edges.
Split does nothing when applied to a single edge in
themiddleofamesh. Theverticesattheendof
affected edges must be separable for this option
to work. For example, it would work on a single
edge that intersects an existing border, since the
border vertex can be split in two. Additionally, two
adjacent edges could be split in the middle of a
grid or sphere, since the shared vertex can be split.
Ex trude—Lets you extrude edges manually via
direct manipulation in the viewport. Click this
button, and then drag vertically on any edge to
extrude it.
When extruding a vertex or edge interactively in the
viewport, you set the extrusion height by moving the
mouse verticall y and the b ase width by moving the mou se
horizontally.
Extruding an edge moves it along a normal and
creates new polygons that form the sides of the
extrusion, connecting the edge to t he object. The
extrusion has either three or four sides; three if the
edge was on a b order, or four if it was shared by
two polygons. As you increase the length of the
extrusion, the base increases in size, to the extent
of the vertices adjacent to the extruded edge’s
endpoints.
Important aspects of edge extrusion are:
• The mouse cursor changes to an Ext rude cursor
when over a selected edge.