non parametric curves and the studio spline tool... (NX6)

[JohnFox]

Hi,
if I want to create a parametric driven object that contains studio spline curves what approach should I follow? I can dimensionally and geometrically constrain all my basic curves in my sketch but if I want to then try and change the size or shape of my object parametrically at a later date the non-parametric studio spline curves it contains present a problem. Do I have to draw them again? How should I think about and tackle this problem...

many thanks,
John

 

[JohnRBaker]

You can constrain the slope at the ends as well as at the individual points of a spline, as well as actually dimensioning the spline points relative to other objects. Or you could just apply a 'shape' constraint to the overall spline. Open the attached part and double-click the sketch and edit the length of the rectangle from 400mm to say 200mm and note the behavior of the two splines.

Both Splines were created with the 2 endpoints constrained Coincident to and matching the slope to the horizontal sides of the rectangle and with the 3 intermediate points un-dimensioned, however the Spline the goes from the upper left corner to the lower right corner was also constrained to maintain a 'Uniform Scale'.

If you're careful and and bit creative (such as adding reference curves used to only constrain the slope of the spline at certain points) you can do some pretty cool stuff with Spline inside a Sketch.

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

http://www.siemens.com/plm

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

To an Engineer, the glass is twice as big as it needs to be.

 

[JohnFox]

Hi John,
great example and explanation! That helps alot...

many thanks,
JohnFox