**Cadfil - Advanced filament Winding software for program generation for all type of filament winding machine.**

**Filter length and filter angle**

To generate an accurate geodesic path the mandrel must have a relatively large number of patches or elements.
Fibre positions are calculated each time the path crosses the boundary of an element.
The number of data points on the fibre path is much greater than the number of points required
to accurately control the machine. Filter length and angle are used to remove (filter out) surplus
data points. Subsequent data points on the fibre path are selected such that the distance between
the points on the **mandrel surface is not less than** the filter length** and** the angle
between the path direction vectors for successive data points is not** greater **than the
filter angle. The default values are suitable for most purposes. The filter values cannot
be zero and the filter angle is not permitted to be greater than 90^{0}. The internal
default is 12 degrees but this can be changed using the SM file variable for
example '$SM-FILTER-ANGLE=20.0 sets a default of 20 degrees.

Using very small filter values can lead to many very small motions on the winding machine. In many cases this leads to 'rough' operation of the machine and can lead to an increase in winding time.