Le 24/06/2011 04:03, SharkD a écrit :
> How do I create a paraboloid where a slice through the object produces a
> circle of a fixed and known size? Thanks!

Slice of paraboloid are circle only when the slice is perpendicular to
the axis of the paraboloid.

Ergo, if the slice is parallel to the z plane, the circle will be
a.(x²+y²) - b = 0

a.(x²+y²) is the square of the radius (r² := b).

If the equation of your paraboloid is (classical) z=k.(x²+y²), it seems
obvious that the slice must have a z so that k.(x²+y²) is the square of
the desired radius.

(i.e. #local z_position = sqrt( pow(r,2)/k );  )


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