Can I make a bicubic patch form into a circle with a math formula?
I know I can manually use the control points to do so, but that's too
labor-intensive.  Can it be performed with a math formula for a circle?

Thanks.

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> Can I make a bicubic patch form into a circle with a math formula?
> I know I can manually use the control points to do so, but that's too
> labor-intensive.  Can it be performed with a math formula for a circle?

Sure, you could do that. Or just use vrotate, that's easier.

Here's a macro with some fudge factors thrown in

#macro bicubic_disc(outer_radus, outer_height, inner_radius, inner_height)
   #local o = <outer_radus, outer_height, 0>;
   #local o2 = <outer_radus*1.15, outer_height, 0>;
   #local i = <inner_radius, inner_height*2, 0>;
   bicubic_patch { type 0 u_steps 3 v_steps 3
      vrotate(o,225*y),vrotate(o2,255*y),vrotate(o2,285*y), 
vrotate(o,315*y),
      vrotate(o2,195*y),vrotate(i,225*y),vrotate(i,315*y), 
vrotate(o2,345*y),
      vrotate(o2,165*y),vrotate(i,135*y),vrotate(i,45*y), vrotate(o2,15*y),
      vrotate(o,135*y),vrotate(o2,105*y),vrotate(o2,75*y), vrotate(o,45*y)}
#end

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"neodasa" <klu### [at] nycrrcom> wrote:
> Can I make a bicubic patch form into a circle with a math formula?
> I know I can manually use the control points to do so, but that's too
> labor-intensive.  Can it be performed with a math formula for a circle?

AFAIK you can shape bicubic patches only into an *approximation* of a circle.
Which doesn't make it easier to come up with a nice clean math formula...

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