Thank you,mmauldin. but, I could not import youe file in to UG. The message is: " The imported part has features that use expressions and is of different units. Use the "ug_convert_part" program."
You can open the part directly to see the geometry. To convert it to mm so that you can import, just start the command prompt form the NX Tools program folder and browse to the folder where this part file is and run:
ug_convert_part -mm spiral_guide.prt. Then it will import. Alternatively, just duplicate the method mmauldin has shown you to make the spiral in your existing part.
thank you for your help. Sorry about my limited computer knowledge. I am using NX5. Looks like your model is the newer version. Could you please convert it to NX5?
In this particular model you can change the value of expression "p7" form 360*num_turns to -360*num_turns.
In general, you can edit the swept feature and change the value for "End Value" of the Angular Law from a positive number to a negative number, or vice versa.
Just because the question originally related to how to define the spiral curve I thought that I might show the use of a helix curve to define the same thing. Depending on your circumstances you can occasionally find more utility in one method than another as you move to more complex examples. However having come to the party late I think Mike's example was in fact the better method of construction for this example. If nothing else it is a great example of a solution that improves upon the question.
In the attached file I have simply added a few features on to the end of Mike's last effort to illustrate the alternative having equivalent results.
