|
|
clipka <ano### [at] anonymousorg> wrote:
>
> In your search you may come across `min_extent()` and `max_extent()`;
> note that these can be used on any object as a /rough/ estimate of the
> region of space occupied by that object, but the values are not
> guaranteed to be exact: `min_extent()` may return lower values
> (sometimes significantly so), while `max_extent()` may return higher
> values (again sometimes significantly so). The only thing guaranteed is
> that the entirety of the object lies /somewhere/ within those bounds.
>
I've always been curious about why this is so. For example, assume a short
cylinder (short in y) and with no rotations. Taking the min_extent/max_extent of
that object as-is, the resulting 'bounding box' shape tightly hugs that object
(meaning, the bounding-box 'axis planes' just touch the object.)
But if the object is rotated (around all three axes, for argument's sake), the
resulting bounding-box (its planes) are generally some distance away from any of
the cylinder's surfaces. I.e., there are gaps of empty space between object and
bounding box. I'm sure that there IS a technical reason for this; but a simple
(naive!) question would be: Why does rotating an object 'mess up' the
bounding-box tightness?
Post a reply to this message
|
|