This op provides a set of operations applicable to the parametric space of spline curves and surfaces. The parametric space, also known as the “domain” of a NURBS or Bezier primitive, is defined by one basis in the U direction and, if the primitive is a surface, another basis in the V direction. The size of the domain is given by the values of the knots that make up the basis.
The Basis op contains both ratio-preserving and non ratio-preserving operations.
If the basis reparameterization does not change the distance ratios between knots, the shape of a NURBS primitive is not affected. If the ratios are not preserved; however, a NURBS primitive will change shape in the area influenced by the modified knots. Additionally, if the primitive is a NURBS or Bezier surface, any profiles it may contain will be affected as well.
Parameters ¶
Group
Subset of spline primitives to operate on.
Edit the U Basis
Enables and disables transformations of the U basis below.
Edit the V Basis
Enables and disables transformations of the V basis below.
Parameterization ¶
Parameterization
Parameterization method.
Unchanged
Does not change the U basis.
Uniform
Distributes all knots evenly.
Chord Length
Computes knot ratios based on primitive chord length.
Centripetal
Similar to chord length, useful for sharp turns.
Manual:Single
Edit knots of first spline primitive individually.
Manual:Propagated
Same as above but copy knots to all other primitives.
Knotslide
Shift clusters of knots within the basis.
Approximate Arc Length
Computes knot ratio based on an approximate primitive arc length.
Knot Sequence
Editable field of knots in ascending order.
Read Basis
Reads knots of first primitive into the field above.
Range
Area of the unit U domain to be shifted.
Bias
Amount and direction of shift in knotslide.
Map ¶
Concatenate
Indicates whether bases should be concatenated.
Origin
New origin of the U basis.
Length
New length of the U basis.
Scale
Multiplier applied to basis at its origin.
Order ¶
Raise To
Enables and disables raising of the basis order.