figure eight curve

[dakeb1]

cartesian:


parameters deifned:


r=radius


d=diameter


expression:


x=2*r*cos(360*t)*sqrt(cos(360*t)^2)<BR itxtvisited="1">y=2*r*cos(360*t)*sin(360*t)<BR itxtvisited="1">z=t*d


It works!


Of course my angles were in degreees not radians!


Holy grail found thanks to bronsona!

 

[dakeb1]

here is the part!





2010-09-06_074042_figure-eight-equation.prt.zip

 

[kdem]

Neat! I had tried something similar but couldn't get it to work. I kept getting a full circle or an error that the curve could not be created. I think the problem for me was the sqrt of the squared term. Thanks for sharing the solution.
Edited by: kdem

 

[dakeb1]

Slight problem with the model, I cannot pattern from the diameter section location of the vss, it drifts off the z axis. Easily fixed, I set up a new offset csys for the curve and patterned that instead.

 

[dakeb1]

Neat! I had tried something similar but couldn't get it to work. I kept getting a full circle or an error that the curve could not be created. I think the problem for me was the sqrt of the squared term. Thanks for sharing the solution.

Yeah, Bronsona said it needs to be like that or the signs can go wrong.

 

[rajib]

The model is slightly modified (with one copy and then pattern) . Its just a matter of giving relations with the "PITCH" parameter. Model attached as zip (please resume all the suppressed features).


2010-09-07_033006_figure-eight.prt.zip

 

[dakeb1]

Rajib,


In actual fact, I can do this without copying or patterning at all, by having a continuous single curve of 'n' coils, represented by: -


n=coils
r=radius
d=diameter
x=2*r*cos(n*360*t)*sqrt(cos(n*360*t)^2)
y=2*r*cos(n*360*t)*sin(n*360*t)
z=t*d*2*n


I can even have the half coil, e.g parameter: coils = 4.5, to make the cable terminate at the opposite end to the start.


Sweet!