You can create a text report with echo() and str() and output it to a .echo
file but you need a bit of post processing to make it look pretty. I.e.
remove ECHO: and the quotes.

You can also generate dimension lines yourself by making a line of length
A1-B2 with text of A1-B1 on it placed at A1 going to B1. You can then
generate a png with those on.

On Wed, 21 Oct 2020 at 07:05, YigalB yigalb@hotmail.com wrote:

If you place two circles then you must have specified the centres of the
circles so you can write an expression for that.

E.g.

c1 = [ some complex expression ];
c2 = [ some complex expression ];

translate(c1) circle();
translate(c2) circle();

echo(c2 - c1);

You can draw a line between centres by translating tiny circles there and
taking the hull. You can use $preview to only show it in the preview and
not appear in the render for STLs.

On Thu, 22 Oct 2020 at 06:41, Yigal B yigalb@hotmail.com wrote:

On 10/21/2020 11:57 PM, nop head wrote:

But, to be clear, you have to know where the points are.  OpenSCAD
won't tell you.

For instance:

translate([10,0,0]) sphere(1);
rotate(27) translate([10,0,0]) sphere(1);

You'd have to do your own trigonometry to find the centerpoint of the
second sphere.

More complicated:

module barsphere() {
    translate([0,-.5,-.5]) cube([10,1,1]);
    translate([10,0,0]) sphere(2);
}

barsphere();
rotate(40) barsphere();

You would not only have to do your own trigonometry, but you'd also have
to "know" what barsphere() does; you'd have to "know" that it puts the
sphere at [10,0,0].

nophead wrote

What you want, is norm(c2-c1)

// two random positions
p1=rands(-50,50,3);
p2=rands(-50,50,3);
// spheres at each point
translate(p1)sphere(r=1,$fn=10);
translate(p2)sphere(r=1,$fn=10);
// calculate distance
distance=norm(p2-p1);
echo(p1=p1,p2=p2,distance=distance);

--
Sent from: http://forum.openscad.org/

to "know" what barsphere() does; you'd have to "know" that it puts the
sphere at [10,0,0].

Yes you have to tell OpenSCAD where things are. It doesn't tell you
anything in return. And yes you frequently need to do trig to place things.

If you want to find where things are after transformations you can write
the transformations as functions on matrices and call multmatrix to do the
positioning and use the same matrix to transform a point like the origin.

There is an example here in my library.
https://github.com/nophead/NopSCADlib/blob/master/printed/corner_block.scad#L51

On Thu, 22 Oct 2020 at 17:45, jjvbhh jjvb-openscad@bassklampfe.de wrote: