Hi Rainer,

The method Michael mentions is the way to go, here's a quick run-down for you and anyone else who's interested.

Create a regular Helix, 'Draw curve > More > Helix'
Draw a line (Green) perpendicular from the start of the Helix to the centre.


Sweep the Green line along the Helix 'Construct > Sweep' and use 'Flat' in the Twist option drop down.


Create a Sphere 'Draw Solid > Sphere' from the centre of the helix and use the end point of Helix for the size.


Then use 'Construct > Curve > Isect' to create an intersection curve between the Sphere and Swept surface, and you have what I call a 'HeliSphere'


Then have fun with it!


Cheers