On Thu, 14 Oct 1999 06:12:00 -0700, Alan Kong
<ako### [at] pacbellNO-SPAMnet> wrote:

>On Wed, 13 Oct 1999 18:24:41 -0500, Larry Fontaine <lfo### [at] isdnet> wrote:
>
>>#macro roundbox [..]
>
>  Hi, David. Does this macro have an advantage over using POV-Ray's
>superellipsoid primitive object?

They are not interchangeable. 

The superellipsoid, by definition, can not have perfectly flat sides
and its fillets are not circular. It is also somewhat slower unless
transparent (because David's macro is using merge). Last thing is,
superellipsoids lack precise dimensional control. They are marginally
bounded by a box { -1, 1 } but precise scaling and positioning
requires trial and error.

A rounded_box has flat sides and circular fillets, renders faster
(unless transparent) and is faster at CSG (if unioned and not merged)
but consumes more memory. Its flat sides sometimes give flooding
highlights which can be avoided by using a superellipsoid (I had this
problem with my washer picture). Lastly, a rounded_box has a constant
circular edge fillet regardless of scale. 


Peter Popov
ICQ: 15002700

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