Hi Folks

Changed jobs several times and had difficulty logging on but here I am...........

I would like to produce an in context coil spring that will flex as the parts move (eventually in a motion study)

Normally I sketch a circle, then create a helix (from the curves menu) then another circle at the end of the helix to represent the wire diameter and eventually complete the spring by sweeping this circle along the helix.

The apparent limitation occurs when producing the helix.  I can use height and revolution, the height representing the spring length and the revolution is the number of turns.  As the spring flexes, the length will change but the revolutions will remain constant. 

The only way I can see to create the length is by inputing a fixed numerical value.  I would idealy like to represent the height by (say) an in-context line drawn between the twwo spring mounting surfaces that will vary as the surfaces move to and from each other and thereby dynamicaly update the changing length.

Really appreciate any suggestions.............

Regards

Cameron