Perhaps use a different variable name for the second one.

On Sun, 20 Oct 2024 at 19:15, Caddiy via Discuss discuss@lists.openscad.org
wrote:

nop head wrote:

Nah, doesn’t help.

include <BOSL2/std.scad>

include <BOSL2/beziers.scad>

x=30;

bezpath = flatten([

bez_begin([-100, 0], 0, 35),

bez_end ([ -20*cos(30), -20*sin(30)], 180+30, 35),

]);

debug_bezier(bezpath);

w=30;

bezpath = flatten([

bez_begin ([ 20*cos(30), 20*sin(30)], 180+30, -35),

bez_end([100, 0], 0, -35),

]);

debug_bezier(bezpath);

You are using bezpath for both curves. A variable only has one value in
open scad so it will draw the second curve twice.

On Sun, 20 Oct 2024, 19:37 Caddiy via Discuss, discuss@lists.openscad.org
wrote:

On 10/20/2024 12:07 PM, nop head via Discuss wrote:

... and should have given a WARNING message.

Advice:  turn on Edit  / Preferences / Advanced / OpenSCAD Language
Features / Warnings / Stop on the first warning.  And then fix every
warning.

Not sure repeat use of variables gives a warning in the last release. It
certainly does in the snapshots.

On Sun, 20 Oct 2024, 20:36 Jordan Brown, openscad@jordan.maileater.net
wrote:

On 10/20/2024 12:39 PM, nop head wrote:

Why I keep a copy of 2021.01 around... yes, it does.

On 10/20/2024 12:47 PM, Caddiy via Discuss wrote:

Uh... no, or not exactly.

[ The following is a bit simplified and therefore wrong.  I'll elaborate
at the end. ]

Every value needs its own name, whether that value is a number, a
string, or some more complex construct like a BOSL2 Bézier path or a
BOSL2 VNF.

Core OpenSCAD squares and circles are modules, not values, and so can't
go into variables at all.  BOSL2 has "square" and "circle" functions
that return lists of points.  Those are values and can go into variables.

OpenSCAD modules do not yield values and so can't go into variables.

OpenSCAD doesn't let you assign the same variable twice, no matter what
you're putting into it.

x = 1;
x = 2;

y = "hello";
y = 123;

z = square(10);
z = circle(10);

are all bad.  In core OpenSCAD, the "z" example is doubly illegal,
because core OpenSCAD does not have square() and circle() functions; it
only has square and circle modules.

[ More advanced and correct, though still not completely correct. ]

That "no duplication" rule is inside one "scope".  Very roughly, braces
start a new scope.  Thus this is OK:

x = 1;
if (something) {
    x = 2;
    echo(x);
}
echo(x);

and will yield

ECHO: 2
ECHO: 1

because the inner assignment creates a new x that then vanishes at the
close brace, revealing the original.

[ Getting pretty close to complete truth. ]

Naked braces, that are not a child of an operator, do not start new scopes.

x = 1;
{
    x = 2;
}

is not legal.  (Which seems like a misfeature; see issue 5386
https://github.com/openscad/openscad/issues/5386.)

"include<>" has sort of scope-like behavior; it's OK to set a variable
in an included file and then override it in the "parent" file. 
Similarly for command-line (and Customizer, I think) settings; they can
duplicate in-file settings and override them.

Jordan Brown wrote:

Well yes, obviously. That’s why i said more like a module, not like a module.

The next thing for me is to turn my Bezier curves from the xy-plane to the xz-plane and then do the yz-plane (which is sort of cosinusoidal) so that everything is around the z-axis. Then it will be possible to rotate the whole lot as a module once to the x-axis and once to the y-axis (with a phase difference between the axes of $t*90).

At the moment there are some values that would seem to need to be xyz coordinates in square brackets, but the Bezier expressions don’t want to do that. I may have some questions.