Say that I want to create a perfect sphere or a perfect torus. How common is support for objects like this in any 3D modeling program?
closed as not a real question by Kyle Sevenoaks, Scott, Ryan, plainclothes, JohnB♦ Jan 8 at 0:11
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I assume that by true curves and perfect sphere you mean unapproximated.
Some 3D software packages are created specifically for polygonal modelling. Any 'curved' shape or object you create there is approximated to segments or polygons and thus is not 'perfect'.
Most of modern 3D software packages support NURBS and/or Bézier curves and surfaces which are 'real' curves and surfaces in terms of how they are handled. However, certain curves and surfaces that exist in real world require certain mathematical apparatus to be exact. For instance, a circle, a sphere or a torus requires NURBS support since Bézier curves or surfaces are only approximating these objects.