7 Replies Latest reply on Dec 2, 2009 11:10 AM by 1-LC4F90

Sine wave along a spline path

Hi I am trying to create a sketch that is basically a sine wave curve along a spline path. I need approx 235 'waves' in the sine. Is there an easy way to create this, as I am also wanting to be able to modify the spline curve, which will then update the sine wave. I created a spline path and then offset a distance and created a series of circles with tangental lines between and cut the lines not required the create the sine wave, but when I modified the spline curve, the tangential relations from the circles fell over, and the sine curve would have to created again along the new spline path.
• Re: Sine wave along a spline path

Check out equation driven curve.  You will need to figure out an equation for your path.  Once you have that add the sine wave to the equation.  See attached.

Base: X^3-2*X^2+1

With Sine: X^3-2*X^2+1+sin(10*x)/5

[0-1]

I hope this helps.

Rob Stupplebeen

• Re: Sine wave along a spline path

This is fairly easy once you know the technique!

I have attached an example.

The accuracy of this method is described here (it is accurate enough for typical engineering/manufacturing work, don't worry about it unless you need it for analysis). https://forum.solidworks.com/message/65343#65343

• Re: Sine wave along a spline path
I agree with Charles.... with one caveat.  The limit for "twist along path" is 100 turns (SW09 at least).  If you need 231 "waves" you will need to "segment" your spline somehow and do three sweeps.
• Re: Sine wave along a spline path

If this is what you are after, you will have to create the 235 arcs manually using the Tangent Arc tool... and the result is a little flakey if you tweak the spline path too much.

• Re: Sine wave along a spline path
I guess some clarification is needed.  Do you want this to be close to a real sine curve?  Because arcs and straight lines aren't particularly close to a true sine curve.
• Re: Sine wave along a spline path
Hi, Thanks for al the ideas, I am after a sine curve as close as possible to a real sine curve. I was thinking of creating a centreline as a construction line and then adding a series of circles along that line at specified increments and then having tangential lines and trimming the excess away. This would mean that if the spline curve was 'opened' out and flattened the sine curve would become a real sine curve. (if that makes sense?)
• Re: Sine wave along a spline path
Sorry, but it doesn't.  Arcs and lines cannot really even come close to an accurate sine curve.  If you want a close approximation, you must use Charles's method.