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parametric control and reuse of a spline

In my work I often need to control a spline with parameters, e.g. width and height, while retaining it basic shape not by poles, but by a scaling mechanism.
For example, I need to scale the black spline (see figure below), adapting its width and height to that of the rectangle. My workflow looks like this:
  • 1. Build the basic spline as featureless: "SPLINE_ORIGINAL" (black)
  • 2. Build construction lines to mark the width and the height of the basic spline: Lines (1~3, dotted) 
  • 3. Build the local CSYS for the basic spline: CSYS_spline
  • 4. Scale the basic spline by the local CSYS and factors adapted to the rectangle: Scale Curve (8) (grey) 
  • 5. Move the grey scaled curve by Pattern Geometry (CSYS to CSYS): Yellow curve.
As you can see, the workflow is very tedious. If scores of splines need to be handled, the job is horrifying!
I'm not sure whether I missed something important, and do hope to have your solutions. Thanks!
ScreenClip [1].png
ScreenClip [3].png
My thread two weeks ago dealt with the same issue. The current post  gives a better description and should make you undertand my workflow better. Sorry for reposting.

Re: parametric control and reuse of a spline

Siemens Phenom Siemens Phenom
Siemens Phenom

Create a Datum CSYS.

Create a sketch on one of the planes of the CSYS consiting of a line (horizonal) and a spline of the shape you want starting at one end of the line and ending at the other.

Add Uniform Scale constraint to the spline.

Either dimension on line or fix one end of line.

Can change the scale of the spline by changing length of the line in the sketch.

Can change the possion by moving the Datum CSYS.

Can create another by copy and pasteing the sketch to another CSYS.


Steve V

Re: parametric control and reuse of a spline


Hi, @StevenVickers  Thanks for your reply!


Spline in sketch can have two types of constraints: Non-uniform Scale and Uniform Scale.


  • Non-uniform Scale allows scaling in one direction (from start to end).
  • Uniform Scale allows scaling in X and Y directions by the same factor.

Both of them don't allow scaling in X direction by factor A and in Y direction by factor B at the same time.


I'm not sure whether I missed something important.