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See also: About Splines
Creates a spline curve entity. A Spline is a smooth curve which passes through each point in a set of data points or fit points. Spline curves are typically used where accuracy must be maintained at the fit points, but is unnecessary between the fit points.
The Spline is made up of a chain of smaller sub-curves. These sub-curves straddle the gaps between consecutive fit points. All but the first and the last fit points form the junction between one sub-curve and another. At these junctions, the sub-curves are constrained to join together smoothly. The route that a sub-curve takes between one fit point and the next is governed by the Break Points option that you select when creating the Spline curve.
Tolerance - Specifies a value that alters the displayed smoothness of the curve. The smaller the tolerance value, the smoother the curve. Note that this is a display function only and does not alter the mathematically correct shape of the curve.
Start Angle - Specifies the slope (in degrees) at the start of the curve.
End Angle - Specifies the slope (in degrees) at the end of the curve.
Break Points - Selects how the routes between each fit point are chosen:
Uniform - Use only when the fit points are spaced evenly. An uneven spacing results in unwanted loops and wiggles in the path.
Chord Length - The spline takes into account the actual distance between the fit points.
Name - Specifies a name for the spline curve entity. Use this name later to select the entity.
Once you have created a Spline, you do not need to retain the construction
points as their co-ordinates are retained in the EdgeCAM definition of
the Spline.
You can control the tangent angles at the start and end of the Spline.
The curve segment between each pair of points is defined by three mathematical equations (one for each of the x, y and z axes). For example:
x = f(u) = a + bu + cu2 + du3.
EdgeCAM only creates cubic Splines (of degree 3 - the degree of the equation is the highest value of n in un, so the previous example would be of degree 3). However, EdgeCAM does support Splines of any order, so you can import Splines of a higher order from other CAD systems.