Modeling with NURBS,Subdivisions, and Deformers - Introducing Maya 2011 - page 164

Planar Surface
A planar surface uses one perfectly flat curve to make a two-dimensional cap in the shape
of that curve. It does this by laying down a NURBS plane (a flat, square NURBS primi-
tive) and carving out the shape of the curve like a cookie cutter. The resulting surface is a
perfectly flat, cutout shape, also known as a trimmed surface because the “excess” outside
the shape curve is trimmed away.
To create a planar surface, draw and select the curve and then choose Surfaces ➔
Planar.
You can also use multiple curves within each other to create a planar surface with
holes in it. A simple planar surface is shown on the left side of Figure 5.7. When a second
curve is added inside the original curve and both are selected, the planar surface is cre-
ated with a hole. On the right side is the result when the outer curve is selected first and
then the inner curve is selected before Surfaces ➔ Planar is chosen.

Figure 5.7
A planar surface
based on a single
curve (left). A planar
surface based on a
curve within a curve
to create the cutout
(right).

A planar surface is great for flat lettering, for pieces of a marionette doll or paper
cutout, or for capping the ends of a hollow extrusion. Planar surfaces are best left as flat
pieces, however, because deforming them may not give the best results. In addition, it's
sometimes best to create the planar surface as a polygon. You'll see how to convert sur-
faces to polygons later in this chapter. The following quick exercise will give you an idea
of what to look out for when creating polygons from surfacing techniques:
1. In the Surfaces menu set, select Create ➔ NURBS Primitives ➔ Circle twice to create
two circles.