The important thing to know here is that OpenSCAD does not behave like
a conventional programming language. What look like variables in
OpenSCAD really aren't variables. They are perhaps better thought of as
named constants - and they only last to the end of the scope that they
are created in.
So for instance:
flag = true;
v = 1;
echo(v);
if (flag) {
v = 2;
echo(v);
} else {
v = 3;
echo(v);
}
echo(v);
In a conventional programming language, that would print 1, 2, 2,
right? In OpenSCAD, the v=2 only lasts until the end of that block, and
so what you get is:
ECHO: 1
ECHO: 2
ECHO: 1
If you want to have a "variable" have a value that depends on a
conditional, you have to use the a?b:c construct:
v = flag ? 2 : 3;
The important thing to know here is that OpenSCAD does *not* behave like
a conventional programming language. What look like variables in
OpenSCAD really aren't variables. They are perhaps better thought of as
named constants - and they only last to the end of the scope that they
are created in.
So for instance:
flag = true;
v = 1;
echo(v);
if (flag) {
v = 2;
echo(v);
} else {
v = 3;
echo(v);
}
echo(v);
In a conventional programming language, that would print 1, 2, 2,
right? In OpenSCAD, the v=2 only lasts until the end of that block, and
so what you get is:
ECHO: 1
ECHO: 2
ECHO: 1
If you want to have a "variable" have a value that depends on a
conditional, you have to use the a?b:c construct:
v = flag ? 2 : 3;
