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Point Curve on Surface 1175
Point Cur v e on S urf ace
Selec t NURBS o b je ct. > M odify panel > Create Curves
rollout > Dependent Curves group box > Point on Surf
button
Select NURBS object. > Modify panel > NURBS toolbox >
Create Point Cur ve on Surface button
Apointcurveonsurfaceissimilartoaplainpoint
curve,butitliesonasurface. Youcreateitby
drawing rather than projecting from a different
cur ve. You can use this curve ty pe for tr imming
(page 1–1080) the surface on which it lies.
Trimmingasurfacewithapointcurveonsurface
There are two methods for drawing and edit ing
cur ves on sur faces: drawing in a viewport, or
using the Edit Curve on Surface dialog. The choice
is useful be cause you draw in two d imensions, with
a mouse or other pointing device, while the curve
on a sur face can exist in three dimensions. The
more complex the 3D surface, the more effort it
can require to create and edit a curve on a surface.
Visual feedback can help you draw the curve. The
point whose surface you first click is shown as a
blue square , and the sur face’s minimum UV point
is shown as a plus sign (+). As you draw the curve,
it is displayed interactively in viewports.
Dra wing in a Viewpor t
When you click to position a point, the click is
projected in the viewport’s Z dimension. That is,
your click is projected "through the screen" and
ontothesurface.Thisisastraightforwardwayto
create a curve on a surface if the portion of the
surfacewherethecurvewilllieisclearlyvisiblein
the viewp ort. However, this method doesn’t let
you place p oints on surface locations that are not
visible in the v iewport (they are on back faces, lie
behind other geometry, and so on).
Using the Edit Cur ve on S ur f ace Di alog
The Edit Cur ve on Surface dialog (page 1–1229)
letsyoueditcurvesonsurfacesasyoueditregular
curves in a viewport. The main part of the dialog
is a two-dimensional view of the surface. The
controls provide typical curve editing functions.
Whileyouarecreatingapointcurveonsurface,
the2DViewtogglecontrolsdisplayoftheEdit
Curve on Surface dialog.
You can edit the points in point curves on surfaces
at the Point sub-object level (page 1–1123),asyou
edit other kinds of points. You can transform
points in point curves on surfaces, but you can’t
move the points off the surface. Using the Point
sub-object level is an alternative to editing these
points by using t he Ed it Curve on Surface dia log .