This topic describes
the controls for CV sub-objects that lie on curves. A rollout labeled
CV contains the CV sub-object controls for NURBS models. In addition
to the CV rollout described here, the Curve CV sub-object level
In you can edit the CVs
curves on surfaces as you edit other kinds
of curve CVs. You can transform CVs in CV curves on surfaces, but
you can't move the CVs off the surface. Using the Curve CV sub-object
level is an alternative to editing these CVs by using the
on Surface dialog.
To transform curve CV sub-objects:
- At the Curve CV sub-object level, select one or more CVs.
The sub-object selection
tools are the same as for other kinds of sub-objects. You can also
use the H key while the
Shortcut Override toggle is on. See
The Selection group box,
described under "Interface" later in this topic, provides some additional
options for selecting CV sub-objects.
- Activate (Select And Move) or another
transform and then drag in a viewport to transform the selection.
The shape of the model
changes as you interactively transform the CVs.
Rotate and Scale are
useful only when you've selected multiple CVs.
- When you transform NURBS
CV sub-objects, the Lock Selection Set button can be useful. You
can make a selection in one viewport, click Lock Selection Set (or
press the Spacebar), and
then transform the selection in a different viewport.
- When you move CV sub-objects, move them
as systematically as possible to avoid "getting lost."
To use the keyboard to select curve CV
You can select curve
CV sub-objects using the Ctrl key
and the arrow keys. The arrows traverse the sub-objects in the order
they were created. To do so, follow these steps:
- Turn on (Keyboard Shortcut Override
- Click or drag to select
- Hold down Ctrl and
use the arrow keys to move among the CV sub-objects.
For CVs on curves, the
arrow keys traverse the CV selection along the length of the curve.
The arrow keys don’t move between curve sub-objects.
You can also use the H keyboard shortcut (while the Keyboard
Shortcut Override Toggle button is on) to display a dialog and select
CVs by name. Ctrl+H displays
only the names of CVs directly beneath the mouse cursor.
To remove a CV from a curve:
- Select a CV.
- Click Delete.
Keyboard shortcut: Delete
The CV is deleted and
the shape of the curve is updated.
A CV curve must have
at least one more CV than the
To add a CV to a curve:
- Turn on Refine.
- Click the curve where you want to add
A CV is added at the
location you clicked. Neighboring CVs move away from the new CV
in order to preserve the original curvature.
To add CVs and extend the length of a curve:
- Click to turn on Extend.
- Move the mouse over a CV curve. The curve
is highlighted in blue, and one of the curve's ends displays a box
to show where the curve will be extended.
- Drag from the highlighted end CV, and
then release the mouse button.
New CVs are added beyond
the original length of the curve.
To fuse two CVs:
- Turn on Fuse.
- Click a CV without releasing the mouse
button. Drag to another CV, and then release the mouse button.
The first CV you choose
acquires the position of the second CV, and becomes dependent to
it. If the first CV has an animation controller, the controller
is discarded. If the second CV has an animation controller, the
first CV acquires it too.
Fused CVs display in
purple by default.
To unfuse fused CVs:
- Select the fused CV.
- Click Unfuse.
Now you can move and
edit the two CVs independently.
To transform a region:
- Using sub-object selection, select one
or more CVs for the center of transformation.
- Turn on Soft Selection.
- Transform the CV.
A region around the selected
CV is transformed accordingly.
Move is the most common
transform to use. Rotate and Scale can be used with a non-local
If Soft Selection
appears not to be working, the Falloff value might be too small
for the size of your surface. On the
, increase the value
of Falloff so it encompasses other points or CVs.
In addition to the CV
rollout described here, the Curve CV sub-object level also displays
Curve sub-object selection
- Single CV
(The default.) When on, you
can select individual CVs by clicking, or groups of CVs by dragging
- All CVs
When on, clicking or dragging
selects all the CVs in the curve.
Shows either "No CVs selected",
"Multiple CVs selected", or "CurveName(index)", where "CurveName"
is the name of the CV's parent curve, and "index" is the CV's U
location along the length of the curve. You can't edit the Name
field to customize the names of CVs.
If CVs are fused, the
Name field shows the name of the first CV.
Adjusts the weight of
the selected CVs. You can use a CV's weight to adjust
the CV's effect on the curve. Increasing the weight pulls the curve
toward the CV. Decreasing the weight relaxes the curve away from
Increasing weight is
a way to harden a curve; that is, to sharpen its curvature at a particular
By default, the weight
is 1.0 for the CVs of NURBS objects that you create on the Create panel
or the NURBS sub-object creation rollouts. The weight of CVs in
geometry that you convert to NURBS can vary, depending on the object's original
You can change the weight
when multiple CVs are selected. Using the Weight field or spinner
while multiple CVs are selected assigns all of them the value you
choose. Because weights are relative to each other (rational), using
the Weight control when all CVs are selected has no visible effect.
Click to hide the currently
- Unhide All
Click to unhide all hidden
Fuses a CV to another
CV. (You can't fuse a CV to a point, or vice versa.) This is one
way to connect two curves. It is also a way to change the shape
Fusing CVs does not combine
the two CV sub-objects. They are connected but remain distinct sub-objects
that you can unfuse later.
Fused CVs behave as a
single CV until you unfuse them. Fused CVs behave similar to a single
point, but the property of multiplicity for coincident CVs also
Curve.) The fused CVs have proportionally
more influence on the curve. The curve can become sharper in the
fused CVs' vicinity, or even angular if more than two CVs are fused
Fused CVs are displayed
in a distinct color. The default is purple. (You can change this color
panel of the
User Interface dialog.)
Refines the curve by adding
WarningWhen you add CVs
with Refine, you lose the animation controllers for all CVs on the
As you move the mouse
over the CV curve, a preview of the CVs that will be added, and
their locations, is displayed in blue.
Deletes the selected CVs.
Inserts CVs into the curve.
Click Insert and then click the curve where you want to insert the
new CV. Inserting CVs is similar to refining with CVs, except that other
CVs in the curve do not move. This means that the shape of the curve
changes when you insert.
Inserting CVs does not
remove animation from the curve, as refining does.
Extends a CV curve. Drag from
the end of a curve to add a new CV and extend the curve.
WarningWhen you add points
with Extend, you lose the animation controllers for all points on
- Remove Animation
Removes animation controllers
from the selected CVs.
- Display Lattice
When on, displays the
lattice that surrounds CV curves. When
off, the control lattice isn't shown in viewports. Default=on.
- CVs Selected
This text field shows
how many CVs are currently selected.