Spline¶
SPLINE curve (DXF Reference), all coordinates have to be 3D coordinates even the spline is only a 2D planar curve.
The spline curve is defined by control points, knot values and weights. The control points establish the spline, the various types of knot vector determines the shape of the curve and the weights of rational splines define how strong a control point influences the shape.
To create a Spline
curve you just need a bunch of fit points  knot values and weights are optional
(tested with AutoCAD 2010). If you add additional data, be sure that you know what you do.
See also
Since ezdxf v0.8.9 Spline
stores fit and control points, knots and weights as packed data
(array.array
).
Subclass of 

DXF type 

Factory function 
see table below 
Inherited DXF attributes 

Required DXF version 
DXF R2000 ( 
Factory Functions¶
Basic spline entity 

Spline control frame from fit points 

Open uniform spline 

Closed uniform spline 

Open rational uniform spline 

Closed rational uniform spline 

class
ezdxf.entities.
Spline
¶ All points in WCS as (x, y, z) tuples

dxf.
degree
¶ Degree of the spline curve (int).

dxf.
flags
¶ Bit coded option flags, constants defined in
ezdxf.lldxf.const
:dxf.flags
Value
Description
CLOSED_SPLINE
1
Spline is closed
PERIODIC_SPLINE
2
RATIONAL_SPLINE
4
PLANAR_SPLINE
8
LINEAR_SPLINE
16
planar bit is also set

dxf.
n_knots
¶ Count of knot values (int), automatically set by ezdxf (read only)

dxf.
n_fit_points
¶ Count of fit points (int), automatically set by ezdxf (read only)

dxf.
n_control_points
¶ Count of control points (int), automatically set by ezdxf (read only)

dxf.
knot_tolerance
¶ Knot tolerance (float); default =
1e10

dxf.
fit_tolerance
¶ Fit tolerance (float); default =
1e10

dxf.
control_point_tolerance
¶ Control point tolerance (float); default =
1e10

closed
¶ True
if spline is closed. A closed spline has a connection from the last control point to the first control point. (read/write)

control_points
¶ VertexArray
of control points in WCS.

fit_points
¶ VertexArray
of fit points in WCS.

knots
¶ Knot values as
array.array('d')
.

weights
¶ Control point weights as
array.array('d')
.

control_point_count
() → int¶ Count of control points.

fit_point_count
() → int¶ Count of fit points.

knot_count
() → int¶ Count of knot values.

construction_tool
() → BSpline¶ Returns construction tool
ezdxf.math.BSpline
.New in version 0.13.

apply_construction_tool
(s: BSpline) → Spline¶ Set SPLINE data from construction tool
ezdxf.math.BSpline
or from ageomdl.BSpline.Curve
object.New in version 0.13.

flattening
(distance: float, segments: int = 4) → Iterable[Vector]¶ Adaptive recursive flattening. The argument segments is the minimum count of approximation segments between two knots, if the distance from the center of the approximation segment to the curve is bigger than distance the segment will be subdivided.
 Parameters
distance – maximum distance from the projected curve point onto the segment chord.
segments – minimum segment count between two knots
New in version 0.15.

set_open_uniform
(control_points: Sequence[Vertex], degree: int = 3) → None¶ Open Bspline with uniform knot vector, start and end at your first and last control points.

set_uniform
(control_points: Sequence[Vertex], degree: int = 3) → None¶ Bspline with uniform knot vector, does NOT start and end at your first and last control points.

set_closed
(control_points: Sequence[Vertex], degree=3) → None¶ Closed Bspline with uniform knot vector, start and end at your first control point.

set_open_rational
(control_points: Sequence[Vertex], weights: Sequence[float], degree: int = 3) → None¶ Open rational Bspline with uniform knot vector, start and end at your first and last control points, and has additional control possibilities by weighting each control point.

set_uniform_rational
(control_points: Sequence[Vertex], weights: Sequence[float], degree: int = 3) → None¶ Rational Bspline with uniform knot vector, deos NOT start and end at your first and last control points, and has additional control possibilities by weighting each control point.

set_closed_rational
(control_points: Sequence[Vertex], weights: Sequence[float], degree: int = 3) → None¶ Closed rational Bspline with uniform knot vector, start and end at your first control point, and has additional control possibilities by weighting each control point.

transform
(m: Matrix44) → Spline¶ Transform SPLINE entity by transformation matrix m inplace.
New in version 0.13.

classmethod
from_arc
(entity: DXFGraphic) → Spline¶ Create a new SPLINE entity from CIRCLE, ARC or ELLIPSE entity.
The new SPLINE entity has no owner, no handle, is not stored in the entity database nor assigned to any layout!
New in version 0.13.
