Figure-8 Helix
Figure-8 Helix
(OP)
Hi guys,
Is it possible to do a helical type sweep, but in a figure-8 format?
e.g. imagine a spring wound in a figure-8 style, around two parallel mandrels?
cheers,
Dave
Is it possible to do a helical type sweep, but in a figure-8 format?
e.g. imagine a spring wound in a figure-8 style, around two parallel mandrels?
cheers,
Dave





RE: Figure-8 Helix
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RE: Figure-8 Helix
Curve by Equation can do this. It just depends on how exact you want your circles or if you want exact radii or not.
/* Equation Data
R=5
x=R*sin(20*t*360)
y=t*40
z=2*R*cos(10*t*360)
I will look and see if another method works better.
You may want to try using relations with a variable like(-1)^n to alternate positive and negative values for x to go positive and negative with absolute value between 0 and the Helix diameter or G=1-cos(value) which would have a range of (0-2)
Michael
RE: Figure-8 Helix
Been unable to login to eng-tips for a few weeks. Thank you very much for your response, it was most helpful.
David
RE: Figure-8 Helix
I modified the equations a bit to include editable parameters (number of coils, aspect ratio, cable diameter) and to make the cable touch at the cross-over point: -
x=RADIUS*sin(COILS*2*t*360)
y=t*COILS*CABLE_DIA*50
z=ASPECT*RADIUS*cos(COILS*t*360)
RE: Figure-8 Helix
x=RADIUS*sin(COILS*2*t*360)
y=t*COILS*CABLE_DIA*2
z=ASPECT*RADIUS*cos(COILS*t*360)
RE: Figure-8 Helix
Any ideas anyone?
RE: Figure-8 Helix
Dave told me he was using Wildfire 3 so I went ahead and created a trailfile which i will upload here as well
Michael
RE: Figure-8 Helix
r=500
d=65
x=2*r*cos(360*t)*sqrt(cos(360*t)^2)
y=2*r*cos(360*t)*sin(360*t)
z=t*d
Excellent work bronsona from the MathCad forum!!
Thanks
Dave
RE: Figure-8 Helix
Thanks to all for your efforts in solving this. It was realy doing my head in, I knew it must be possible to do this with a single equation.
Dave
RE: Figure-8 Helix
RE: Figure-8 Helix
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!