Convert Curve Dialog (NURBS)

Command entry:

Modify panel

Select a NURBS curve sub-object.

Curve Common rollout

Convert Curve button

This dialog is a general way to convert one kind of a curve to another or to adjust a curve's parameters.

Interface

Point Curve and CV Curve: Choose whether to convert to a point curve or a CV curve. If the curve is already of the type you chose, the settings in this dialog don't convert it, but do change its properties. Default=CV Curve.

CV Curve options

These are the options when you choose CV Curve.

Number: When chosen, the spinner sets the number of CVs in the CV curve.
Tolerance: When chosen, 3ds Max calculates the number of CVs. This option rebuilds the curve according to accuracy. The lower the Tolerance value, the more accurate the rebuild. Increasing Tolerance enables the curve to be rebuilt using fewer CVs.

Reparameterization group

These controls let you reparameterize the CV curve and turn on automatic reparameterization.

Chord Length: Chooses the chord-length algorithm for reparameterization.

Chord-length reparameterization spaces knots (in parameter space) based on the square root of the length of each curve segment.

Chord-length reparameterization is usually the best choice.
Uniform: Spaces the knots uniformly.

A uniform knot vector has the advantage that the curve changes only locally when you edit it. With chord-length parameterization, moving any CV can potentially change the entire sub-object.
Maintain Parameterization: When on, the curve is automatically reparameterized as you edit it, using the currently active method of reparameterization. When off, no reparameterization happens unless you use a dialog to specifically request it. Default=on.

Point Curve options:

These are the options when you choose Point Curve.

Number: Sets the number of points in the point curve.
Tolerance: When chosen, 3ds Max calculates the number of points. This option rebuilds the curve according to accuracy. The lower the Tolerance value, the more accurate the rebuild. Increasing Tolerance enables the curve to be rebuilt using fewer points.
Preview: When on, the effect of the conversion is previewed in viewports. Default=on.