[OpenSCAD] Evaluating imported STL's

Lucas Vinicius Hartmann lucas.hartmann at gmail.com
Thu Jun 16 21:36:42 EDT 2016


Unfortunately the point hacked with scale(0) is not well behaved. The code
below crashed openscad every time I asked it to render...

module point(at=[0,0,0]) {
    translate(at) scale(0) cube();
}

minkowski() {
    point([0,0,0]);
    point([1,0,0]);
    point([0,1,1]);
    point([0,0,1]);
}


--
Lucas Vinicius Hartmann

Dizem que se você rodar o CD do Windows ao contrário ele mostra uma
mensagem demoníaca... Mas isso nem é o pior, se você rodar ele normal ele
instala o Windows!

2016-06-16 18:26 GMT-03:00 Ronaldo <rcmpersiano at gmail.com>:

> Rudolf,
>
> I had taken mistakenly your scale(0) sphere(). I had assumed (without
> testing it) that it is incorrectly evaluated as an empty set. But no, it is
> a point: the origin! Preview that:
>
> > hull() {
> >     sphere(5);
> >     translate([0,0,12]) scale(0) sphere();
> > }
>
> The result is mathematically correct: the convex hull of the sphere(5) with
> the point [0,0,12]. So, scale(0) (or equivalently your multmatrix stuff)
> transform anything into a point, the origin, in a way that can be
> translated, rotated and scaled again.
>
> Why didn't you get anything in the stl file? Because there is no facets in
> scale(0) sphere() just one vertex.
>
> Besides,
>
> > minkovsky() {
> >     cube(5);
> >     translate([0,0,12]) scale(0) sphere();
> > }
>
>  is equivalent to translate([0,0,12])  cube(5), which is correct because
> scale(0) sphere() is not the empty set.
>
>
>
> --
> View this message in context:
> http://forum.openscad.org/Evaluating-imported-STL-s-tp17682p17723.html
> Sent from the OpenSCAD mailing list archive at Nabble.com.
>
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