Lisp for inscribing a Sphere inside a 3D region / surface

[Anonymous]

Hi to all,

I need lisp code to incribe a sphere inside a 3d region made by an irregular surface or polylines (contourlines), sphere sould be of maximum radius, center lie above zere elevation and sphere my not extend at any point from the region / surface.

kindly help me in this pursuit.

thanks in abvance......