Attaching a law helix to a straight curve

[Cradders]

Hello,

I've been trying to create a law helix that follows a straight line as its centre point. I create a spline from three points referenced from the straight line and generate the law helix from that. When I change or move the original straight line curve in some way, the law helix remains in the same place. I've attached a file - try changing the straight line's length or moving it around - the spline and other geometry adjust accordingly, the helix does not. Any help would be greatly appreciated!
This is eventually for use as a UDF - (and it works with the exception of the helix so far). I select a straight line of any orientation in a structure and it should create a law helix that follows it. For this reason, I can't include the original straight line's length as a numerical input to begin with, nor can I include any global references. All references must come from this original straight line, which until this point I have achieved.

Many thanks,

James

 

[JohnRBaker]

Unfortunately the origin of a helix can not be moved, at least not without defining the entire helix using mathematical formulas.


John R. Baker, P.E.
Product 'Evangelist'
NX Design
Siemens PLM Software Inc.
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

 

[Cradders]

Ah well, thats a shame! Thanks anyway.

 

[hudson888]

James,

It isn't that hard to define a helix as a law curve and allow that you may be able to get something of a useful result.

I have previously seen this topic posted in the forum. Try this and perhaps a quick search for others if it does not suffice. Law curves are a bit hairy to start with but not so tough to handle once you get the hang of your first one.

http://www.eng-tips.com/viewthread.cfm?qid=198966

Regards

Hudson