Hi All,
I need a bit of help with some geometry, my maths in this area is a bit
rusty.
I want to be able to draw a "cylinder" between any two arbitrary points in
space, x1,y1,z1 and x2,y2,z2 but to draw the cylinder I need to rotate and
translate it i.e.
translate([x1,y1,z1])
{
rotate(a=[a, b, c])
{
cylinder(h=length, d=dia);
}
}
translate is easy, it's just x1,y1,z1 and cylinder length is easy, its is
square root of the sum of (xlength^2)+(ylength^2)+(zlength^2) but I just
can't seem to get the angles to rotate correct.

Has anyone done a module like this that they would be willing to share ?
Or is there another, easier way that doesn't require the sperical
coordinates ?

Many Thanks
PhilipJ

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We had this theme some weeks ago. Ronaldo's mirror solution is brilliant.
http://forum.openscad.org/Rotation-question-tp24970p25000.html

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Also if you can accept spherical ends you can simply translate two spheres to
the end points and take the hull. That is better if you want to join them up
end to end.

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Hi,

I did it with hull() as you suggest but it was rather slow and as there are
going to be a lot of these "rods" I wanted to try a different method by
adding a cylinder to fill in between the two spheres.

My aim is to draw up a geodisic dome by specifying the "node" points in
x,y,z coordinated, then create an stl file to 3D print it.

thanks
PhilipJ

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You can also try a  *
https://github.com/runsun/OpenSCAD_Tips/blob/master/snippets.md#line
Line()*  function, which is also based on one of Ronaldo's codes.

$  Runsun Pan, PhD $ libs: scadx , doctest , faces ( git ), offline doc ( git ), runscad.py ( 2 , git ), editor of choice: CudaText  ( OpenSCAD lexer ); $ Tips ; $ Snippets

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Hi again,

I tried the hull() method with just 4 rods and it took 6 seconds to render
when the file was double clicked compared to almost instanteneous (as fast
as openSCAD opens, the image is there on the screen).

I'm still using Version 2015.03-2, could this be a problem ?

code is:

$fn=100;

rod_dia=3;

module rod(x1, y1, z1, x2, y2, z2, d)
{
hull()
{
translate([x1,y1,z1])
sphere(d/2);
translate([x2,y2,z2]) {
sphere(d/2);
}
}
}

rod(0,0,0, 10,10, 30, rod_dia);
rod(20,0,0, 10,10, 30, rod_dia);
rod(0,20,0, 10,10, 30, rod_dia);
rod(20,20,0, 10,10, 30, rod_dia);

regards
PhilipJ

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Hi, thanks for the link.

I'm still trying to learn the language of openSCAD so could you explain:
in the module first line it says:
"module Line( pts, r=0.05, closed=false, color=undef, transp=1, fn=4 )"

what is "pts" ?
I assume it is the points for the line but how do I pass them into the
module through this one variable ?

As an example: how would I draw a line from 0,0,0 to 30,30,30 ?

Many thanks for your time
PhilipJ

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