8

1138 Chapter 9: Sur face Modeling
The small circle indicates the first ver tex.
To turn a cur ve that lies on a sur face into a Point
Curve on Surface:
1.
Select the cur ve sub-object, and then click
Make COS.
Make COS is unavailable unless the curve
already lies on a surface; for example, it is a U
Iso curve.
2. The Convert Curve on Surface dialog (page
1–1228)
is displayed.
Choose CV Curve on Surface to create a CV
curve,orPointCurveonSurfacetocreatea
point curve. The Number of CVs or Number of
Points values let you specify the complexity and
accuracyofthenewcurveonsurface.IfPreview
is on, the new curve is previewed in viewports.
This can help you choose the number.
To reverse a curve:
• Select a curve sub-object and then click
Reverse.
Reversing a curve affects the blend surface that depends
on it.
To join two curves:
1.
In a NURBS object that contains two curve
sub-objects, turn on Join.
2. Click one curve near the end that you want
to connect. Drag to near the end of t he other
curve, and then release the mouse.
The
Join Curve dialog (page 1–1233) is
displayed. This dialog gives you a choice of
methods for joining the curves. Whichever
method you choose, the two orig inal curves are
replaced by a single curve.
3. If the gap between the curves is small (less than
about30units),usetheJoinCurvedialogtoset
the Tolerance value greater than the distance
of the gap.
To br eak a cur ve:
• TurnonBreakandthenclickacurve.
The curve is split into two independent curve
sub-objects. Two coincident (but independent)
points or CVs are created at the location you
clicked: each is the endpoint of one part of the
original curve.