

Am 18.02.2019 um 08:31 schrieb Thomas de Groot:
> OK. So, from the above, why is the difference sphere/box (see my example
> image in p.b.i and p.b.sf) calculating a min_extent.y location
> corresponding to the base of the sphere? I do not grasp that really.
difference {
sphere { ... }
box { ... }
}
is the same as
intersection {
sphere { ... }
box { ... inverse }
}
The sphere has a bounding box of CENTERRADIUS to CENTER+RADIUS.
The box _would_ normally have a bounding box of CORNER1 to CORNER2, but
since it's inverted, it has a bounding box of INFINITY to +INFINITY. (*)
The intersection has a bounding box equal to the intersection between
the sphere's bounding box and the box's bounding box.
The intersection of any finite range A and an infinite range B is equal
to the finite range A.
Thus, the intersection has a bounding box of CENTERRADIUS to
CENTER+RADIUS, just like the sphere.
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