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Law curve along an existing curve

Law curve along an existing curve

Law curve along an existing curve

(OP)
In NX 6 I am using a law curve to create a 2D planer spiral.
x(t) = (r0+r)+cos(n*360*t)
y(t) = (r0+r)+sin(n*360*t)
where r is a function of t and n is the number of turns in the spiral.  z(t) in this case is 0

Now, I want to superimpose a sine wave on the spiral where the amplitude of the sine wave varies in z.  I can to this but using the same equations for x and y and then just add a z(t)= A*sin(n*360*t) but the problem is this sine wave wavelength now varies as r increases from x and y.   I want it to be constant along the length of the spiral.   In otherwords, take the classice sine wave as a function of time, then wrap the straight line time axis into your spiral.  I can't figure out which options to pick to make this curve.  When I select the "by law curve" for the new subtype for the x and y and then specify my z as an equation subtype no curve gets created.  Any Ideas?    

RE: Law curve along an existing curve

(OP)
Nope, that is the same as what I have.  Notice that your wavelength (or period) starts out small at the center of the spiral and then gets larger as you progress to the end of the spiral.  I want the period to be constant as you progress from start to end on the spiral.

RE: Law curve along an existing curve

I think that you mis-interpret the law curve by law curve option,
 It will not "default wrap to" a curve but rather read the "X" (or Y or Z) value from the selected curve.
 If in case your X and Y functions would have been circular, the law curves to follow would have looked like the ones in the attached picture.
Regards,
 Tomas

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