13 Replies Latest reply on Dec 13, 2013 5:59 PM by Roland Schwarz

# Generate a 3D sinusoidal crown curve

Hello all,

I tried to make a '3D sinusoidal crown curve' and I kind of successed only by hand with a sinusoidal-like 3D spline and a circle. Check out the picture that I enclose to see what I mean. The '3D sinusoidal crown curve' is represented in green.

Does anyone know how to make this through a projection feature or combine feature? or even a driven equation?

Cheers,

Charly

• ###### Re: Generate a 3D sinusoidal crown curve

The 'Equation Driven curve' feature drives me crazy. Why can't we make a continious spline?

• ###### Re: Generate a 3D sinusoidal crown curve

Part file attached.

Not sure why we can't but that's the way it is for now. This is the approach I have used for making wave washers.

• ###### Re: Generate a 3D sinusoidal crown curve

Is it possible to take this curve and extrude a cylinder from it? As in the top of the cylinder follows the curve and the bottom of the cylinder is flat. Would it be easier/possible to extrude a cylinder and then cut this curve from it as well? I'm trying to do something very similar to a pipe but haven't found a way to do it yet and this looks very promising.

• ###### Re: Generate a 3D sinusoidal crown curve

You could just model one cycle's worth with eqn curve and make a pattern.  If you really need a continuous curve, make a3D sketch and make a fit spline from the pattern.

• ###### Re: Generate a 3D sinusoidal crown curve

and another thing...

No matter how the curve is developed, I don't use it!  Typically, I use such a curve to make a sinusoidal surface and then intersect that with a cylinder.  This is to get rid of the inevitable interpolation errors that occur.  Final result will then be a curve following the arc of my desire, not just "almost".

• ###### Re: Generate a 3D sinusoidal crown curve

Harold,

Your spline approximation isn't very accurate.

Here is how I do it; no approximation required.

• ###### Re: Generate a 3D sinusoidal crown curve

Yes, a near approximation but simple. If I need accuracy I go for the formula driven curve despite the limitations of not being able to get 360 degrees. Thanks for the model though Charles. I recall this coming up before and looking at this solution. The other downer on my model is that the number of "humps" is not quickly editable.

• ###### Re: Generate a 3D sinusoidal crown curve

Sorry, I re-read my post. I didn't mean to be so negative. Your method looks great (and simple) for modeling a wave spring.

• ###### Re: Generate a 3D sinusoidal crown curve

I didn't take it that way. I was thinking it was clear and to the point. Tone is lacking in text. Seriously, simple but ultimately incorrect and I'm glad you are able to provide a solution.

• ###### Re: Generate a 3D sinusoidal crown curve

Sorry, I couldn't help myself.

• ###### Re: Generate a 3D sinusoidal crown curve

For some reason your previous images are missing, Charles.

• ###### Re: Generate a 3D sinusoidal crown curve

Charles -

How did you get the sketch to generate the wrap?

• ###### Re: Generate a 3D sinusoidal crown curve

Nevermind, I figured it out.