Spiral

This creates an open spiral path that goes round the Y axis. The user can specify the number of times it goes round the Y axis (twirls) and the pitch between twirls.

spiral path

Looking down the Y axis, the X and Z radii determines whether the spiral is circular or elliptical in the manner as the Ring pathThe X and Z radii can be set independantly in the same way as the Ring path.

Creating the Spiral path

Constructors 
Spiral(float radius, float nbr_twirls, float twirl_pitch, int nbrSlices)
Spiral(float radiusX, float radiusZ, float nbr_twirls,
                          float twirl_pitch, int nbrSlices)
Parameter Comments 
radius
 the ring radius round the Y axis. This will create a circular path. 
radiusX, radiusZ
 the ring radius along the X and Z axis. If they differ an elliptical path will be created. 
nbr_twirls
 the number of times the path goes round the Y axis e.g. a value of 2.25 would represent 810° 
twirl_pitch
 the Y distance between succesive twirls of the spiral 
nbrSlices
 the number of slices along the length of the path