Le 24/06/2011 09:05, Le_Forgeron a écrit :
> 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 );  )

Oups,
it's z_position = pow(r,2)/k;

Simpler that way.
-- 
Real software engineers work from 9 to 5, because that is<br/>
the way the job is described in the formal spec.  Working<br/>
late would feel like using an undocumented external procedure.

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