[OpenSCAD] Evaluating imported STL's
Ronaldo
rcmpersiano at gmail.com
Thu Jun 16 12:16:39 EDT 2016
Rudolf,
You raised good points but I will keep mine about Minkowski. The example you
have shown of a vanishing cube is idiosyncratic but for other reasons. I
would expect that
scale(0) sphere;
to be a point, the origin, and not a void set.
In Mathematics, you have a non-void set by doing a Minkowski sum of a point
and a non-void set. I thought we have no way in OpenSCAD to do a Minkowski
sum of a set with only a point or a line segment or a 2D shape due to the
simple fact that we can't express such sets or mix 2D shapes with 3D shapes
in OpenSCAD operations. However, we can at least in Minkowski operations.
> minkowski() {
> cube(1);
> intersection() {
> cube(1);
> translate([$t-1,$t-1,$t-1]) cube(1);
> }
> }
And that is not idiosyncratic. It does exactly what I would expect. The
intersection is not void, it is a square that shrinks to the origin when
$t=0. The scaled sphere should do the same.
BTW, the above "technique" may be very usefull for rounding only some edges
of a solid.
There is much more complexities behind the scene... :)
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