# Curved sides/lines

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## Curved sides/lines

 Hello everybody, is there a way to make curved sides to a cube? i don't mean circulair but more or less hyperbolic curves. something like giving 3 or more points and let the naturally curve between the point be calculated or a formula to calculate grts henk -- Sent from: http://forum.openscad.org/_______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
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## Re: Curved sides/lines

 There is a shape called a cuboid which is possibly something like what you are describing. I wrote an openscad module for them (I should update it, as I have better ways of doing it now) https://www.thingiverse.com/thing:3408435On Wed, 7 Oct 2020, 03:54 Kevig, <[hidden email]> wrote:Hello everybody, is there a way to make curved sides to a cube? i don't mean circulair but more or less hyperbolic curves. something like giving 3 or more points and let the naturally curve between the point be calculated or a formula to calculate grts henk -- Sent from: http://forum.openscad.org/ _______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org _______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
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## Re: Curved sides/lines

 Actually, I think it's called a super-ellipsoid. I guess it's still too early for me. The parameters can be set to cover anything from a cube to a sphere to some rather off hyperbolic shapesOn Wed, 7 Oct 2020, 05:42 A. Craig West, <[hidden email]> wrote:There is a shape called a cuboid which is possibly something like what you are describing. I wrote an openscad module for them (I should update it, as I have better ways of doing it now) https://www.thingiverse.com/thing:3408435On Wed, 7 Oct 2020, 03:54 Kevig, <[hidden email]> wrote:Hello everybody, is there a way to make curved sides to a cube? i don't mean circulair but more or less hyperbolic curves. something like giving 3 or more points and let the naturally curve between the point be calculated or a formula to calculate grts henk -- Sent from: http://forum.openscad.org/ _______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org _______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
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## Re: Curved sides/lines

 In reply to this post by acwest On 2020-10-07 11:42, A. Craig West wrote: > There is a shape called a cuboid which is possibly something like what > you are describing. I wrote an openscad module for them (I should > update it, as I have better ways of doing it now) > https://www.thingiverse.com/thing:3408435That model has all the face normals pointing inwards.... Carsten Arnholm _______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
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## Re: Curved sides/lines

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## Re: Curved sides/lines

 BOSL2 supports 3d beziers, but you'd have to work out how to make the curved "faces" yourself.  I think it's not so easy to make a general "polyhedron smoother".  It is not so difficult either although laborious. You may define a trivariate polynomial deformation using Bezier and apply it to a refinement of the polyhedron. To find the appropriate control points of the deformation may be the painful step. _______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
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## Re: Curved sides/lines

 I suppose if you take each face of the polyhedron (assume a convex polyhedron) you could find the centerpoint and shift it away from the face, and then triangulate.  This forms a pyramid.  Then each triangle could be replaced by a degenerate bezier patch.  Presumably you'd want to match derivatives along the edges, but it's not clear what boundary condition would be desired at the base of the pyramid.   This is a pretty complex endeavor and I think qualifies as "difficult".   Maybe there's some way to keep things simpler?   Ronaldo wrote > BOSL2 supports 3d beziers, but you'd have to work >> out how to make the curved "faces" yourself.  I think it's not so easy to >> make a general "polyhedron smoother". >> > > It is not so difficult either although laborious. You may define a > trivariate polynomial deformation using Bezier and apply it to a > refinement > of the polyhedron. To find the appropriate control points of the > deformation may be the painful step. -- Sent from: http://forum.openscad.org/_______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
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## Re: Curved sides/lines

 In reply to this post by Kevig thanks you all, you give me a good couple of pointers in the right direction. i am going to try them and hopefully it is goig to work. i let you know how it worked out grts h -- Sent from: http://forum.openscad.org/_______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org