This section describes the controls that are common to Point and CV curves. A rollout labeled Curve Common contains the curve sub-object controls for NURBS models.
The selection controls and other common controls are described in Common Sub-Object Controls.
You can delete curve sub-objects by clicking this button.
Turns a CV curve into a point curve.
If the selected curve is already a point curve, you can use Make Fit to change the number of points it has.
For a closed curve, lets you choose a position that becomes the first vertex of the curve.
The first point or CV is significant when you use the NURBS curve like a splineas a Loft path or shape, as a Path Controller path, or as a motion trajectory. For these purposes, the first vertex of the curve is significant. If the curve is a closed curve, you can use Make First to set the curve’s first vertex.
Caution: Using Make First discards any animation controllers for the points or CVs in the curve.
If the curve is open, the first vertex must be one of the endpoints (by default, it is the first you created). The Make First button has no effect, but you can use Reverse to change the curve’s direction.
Reverses the order of the CVs or points in a curve, so that the first vertex becomes the last, and the last becomes the first. (See the previous section, "Make First.")
Joins two curve sub-objects together.
Caution: When you join two curve sub-objects, you lose the animation controllers for all point or CVs on both curves.
Tolerance: A distance in 3DS MAX units. If the gap between the curves you are joining is greater than this value, 3DS MAX creates the join by first creating a blend curve and then joining the three parts. If the gap is less than this value, or if the curves are overlapping or coincident, 3DS MAX doesn’t create the blend.
Creating a blend and then joining the three curves into a single curve is the better technique. The result matches the parent curves well. Without the blend step, the resulting curve can deviate from the parent curves, in order to maintain smoothness. (The amount of deviation depends on how far from tangent the two input curves were at the join.)
A problem arises when there is a gap but it is too small. In this case, 3DS MAX generates the blend but because there isn’t enough room for it, the resulting curve has a loop in it. To avoid this loop, set the Tolerance higher than the gap distance.
If you set the tolerance to 0.0, 3DS MAX chooses a value to use for the Tolerance.
Breaks a single curve into two curves.
While a CV curve sub-object is selected, the CV Curve rollout appears.
The higher the Degree value, the greater the continuity. The lower the degree, the more discontinuous the curve segments become. The degree can’t be less than one or greater than the number allowed by the number of CVs in the curve. Degree 3 curves are adequate to represent continuous curves, and are stable and well behaved. Default = 3.
Setting the degree greater than 3 isn’t recommended, because higher-degree curves are slower to calculate and less stable numerically. Also, you can't create an Offset curve sub-object from a curve whose degree is greater than 3. 3DS MAX supports higher-degree curves primarily to be compatible with models created using other surface modelers.
The number of CVs in a CV curve must be at least one greater than the curve’s degree.
The CV Curve or Point Curve rollout, visible while an independent curve sub-object is selected, lets you make the curve a closed curve.
Closing a curve does not add points or CVs to the curve. The curve retains its original number of points or CVs, and increases its number of segments by one.
Keyboard shortcut: DEL
3DS MAX displays a dialog that asks how many points the new point curve should have.
Reducing the number of points can change the shape of the curve.
If the curve is closed and there is a vertex where you click, this vertex becomes the first vertex. If the curve is closed and there is no vertex where you click, a new vertex is created at the location you click. It becomes the new first vertex, and the curve’s points or CVs adapt to maintain the curvature.
If the curve is open, clicking it has no effect.
The endpoints of the two curve objects are connected by new segments, and the two original curves are replaced by a single curve. (Unlike a Blend curve, the new segment is part of the curve object, not a dependent sub-object.)
The curve is split into two independent curve sub-objects. Two coincident (but independent) points or CVs are created at the location you clickedeach is the endpoint of one part of the original curve.
If the curve is a closed curve, Break creates a single curve object, with its new start and end points at the location you clicked. The new start and end points are coincident but independent.
3DS MAX closes the curve by adding a segment between the curve’s endpoints. The curvature of the new segment blends the curvature of the previous end segments.