and you can use them as you do splines. You can use the Extrude
or Lathe modifiers to generate a 3D surface based on a NURBS curve.
You can use NURBS curves as the path or the shape of a loft. (Lofts
created using NURBS curves are loft objects, not NURBS objects.)
You can also use NURBS
curves as Path Constraint and Path Deform paths or as motion trajectories.
You can assign thickness
to a NURBS curve so it renders as a cylindrical object. (The thickened
curve renders as a polygonal mesh, not as a NURBS surface.)
A curve and the same
curve rendered with thickness
There are two kinds of
NURBS curve objects:
Like other Shape objects,
NURBS curves can contain multiple sub-objects, which are either
dependent or independent.
Creating Curve Sub-Objects
Creating Surface Sub-Objects
Creating and Editing Point Sub-Objects
Common Sub-Object Controls
Editing Point Sub-Objects
Editing Curve CV Sub-Objects
Editing Surface CV Sub-Objects
Editing Curve Sub-Objects
Editing Surface Sub-Objects
Like an object-level
, an object-level NURBS curve is
can contain NURBS curve, NURBS surface, and NURBS point sub-objects.
A NURBS curve remains a Shape object unless you add a surface sub-object
to it; if you do, it converts to a NURBS surface (without changing
Creating Independent Surfaces from NURBS Curve Objects
You can also create NURBS
curve sub-objects by attaching or importing other objects such as
other NURBS curves or spline shapes.
Attaching and Importing 3ds Max Objects
Display Controls for NURBS Models
Both NURBS curves and
NURBS surfaces have a Display area in the Modify panel. These controls
affect which portions of the NURBS geometry are displayed. Next
to the Display area is the button that turns on the toolbox for
- Point Curve
Point curves are
NURBS curves whose
points are constrained to lie on the curve.
- CV Curve
CV curves are
NURBS curves controlled
by control vertices (
The CVs don't lie on the curve. They define a
control lattice that
encloses the curve. Each CV has a weight that you can adjust to
change the curve.