[OpenSCAD] I have a suggestion: shell()...

Dan Zuras 3D threedee at nonabelian.com
Wed Aug 10 13:35:11 CEST 2011


	I find myself spending a lot of time in OpenSCAD
	trying to hollow out things in cases where I'm
	more interested in the surface of a thing than
	the whole body of that thing.

	It can be as simple as rescaling that thing &
	subtracting it from the original.  That works
	for convex scale free objects like spheres &
	cubes.  But usually it involves a some rather
	more difficult construction of the shape of the
	interior & THEN subtracting it from the original.

	It has occured to me that there might be some
	construction involving a minkowski sum to do the
	job.  Say convolving my original shape with some
	small object (like a sphere or even a cube) then
	using union, intersection, & difference to get
	an approximation of the surface.

	But the simplest approach might be if OpenSCAD
	did it for me.  That is, suppose we have a
	function (a functional, actually) that had the
	following syntax:

		shell(thickness) object();

	The semantics would be that shell() takes the
	child object & reduces it to a shell of that
	object which is 'thickness' thick.

	Now I suppose there might be some difficulties
	with objects of non-zero genus.  Maybe not.
	I'm not sure.  And I don't think there is a
	need for a 2D version.  But even the simplest
	of shell functions would be of great help.

	So, is this a reasonable feature to request?


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