Discussion:
[OpenSCAD] module [maybe later function] spiral(rev, hfac, wfac, base_r, sp_r)
r.d. terramir
2018-09-08 22:05:32 UTC
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I need a little help finishing this function to be exact I would like
hfac to be just spiral height in mm from center wire to center wire,
but somehow I endup fraking it up algebra can suck at times but I
think I just not seeing the solution as the germans' say "can't see
the forest because of all the trees"
here is my budding function with instructions :
<code>

module spiral(rev,hfac,wfac,base_r,sp_r){
for (i=[0:0.5:rev*360]){
translate([0,0,i/hfac])
rotate([90,0,i])
translate([base_r-(i/wfac),0,0])
cylinder(r=sp_r, h=0.4, $fn=32);
}
}
/*spiral module instructions
rev= revolutions the spiral makes
hfac= height factor derived by (360*rev)/height in mm)
wfac= incline of the spiral minimum about 15% of rev*360 play with it
to get your best approximate shape) anything under 15% gives you wierd
inverted results before the top
base_r= radius of the bottom spiral
sp_r= radius of the "wire" in mm

*/
// example
spiral(4,60,170,8.75,0.9);
</code>
help
terramir
r.d. terramir
2018-09-08 23:35:48 UTC
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Yes it makes more sense in someways, but it does not have clear
instructions.
The angles are needed instead of the amount of rotations.
terramir
This one might make more sense.
coil.scad <http://forum.openscad.org/file/t2140/coil.scad>
There may be some other way to do things, but this calculates the path the
spring is on and then 'extrudes' along that path.
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r.d. terramir
2018-09-10 02:45:01 UTC
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Well what I did is actually working albeit I had to change some stuff to
negative cause it was winding in the wrong direction. I got the cutout for
the spring I did a wall test print and with a little prep it worked.
So now just design the battery box to go with it.
terramir
If you want to do the angles in degrees instead, you can just replace 360
with 1.
Lines 42-46 and then 63-72 make the tapered windings.
It's possible to do fancier stuff to get something that looks better, but
I'm not sure what application you have in mind.
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Ronaldo
2018-09-09 17:39:20 UTC
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This one might make more sense.
There may be some other way to do things, but this calculates the path the
spring is on and then 'extrudes' along that path.
The coil code is indeed a specific sweep of a circle along a path. It has
however many cracks and it is inadequate for 3d printing for instance. There
are many codes out there aiming to sweep a planar section along a path. The
following is one more version that resorts to the heterodox hull of a
degenerated polyhedron that some people would argue against but which
simplifies the code a lot. For simplicity, this sweep does not avoid
undesirable twists along the path as can be seen by running

sweep(coilpath(), 3dsquare(1));

coil_sweep.scad <http://forum.openscad.org/file/t1275/coil_sweep.scad>







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