Anyone know how to do stereographic projections?  Threonin on
Thingiverse has some OpenSCAD code to map a pixel array (image) onto a
sphere, but that would not produce nice curves.  Examples:

http://www.thingiverse.com/thing:294899

http://www.thingiverse.com/thing:295281

http://www.thingiverse.com/thing:418129

Is there a way to create geometry and then methodically warp each point
on each triangle to conform to the sphere?

Jon

Not really stereo but:
another approach is to look at problem as solids and booleans.
I.e. assume point light source and a surrounding shell of a sphere which you
want to cut into just as in the example links you sent.

So make the (say maze object - perhaps out of individual bloacks perhaps as
one object),
then extrude it and use scale param down to a very small size at the point
light's location,
then do a boolean difference with the sphere shell.

The result is the same.

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Here is an example using the (seldom used?) scale param to linear_extrude.

$fn=30;
module 2D_shape() {
	difference() {
		offset(r=3) {
			square(size=[20,30], center=true);
		}
		square(size=[20,30], center=true);
	}
}

module 3D_projection (dist) {
	linear_extrude(height = dist, center = true, convexity = 4, scale=0.1) {
		children();
	}
}

module shell (rad, thick) {
	difference() {
		sphere(r=rad, center=true);
		sphere(r=rad-thick, center=true);
		translate([0,0,rad/2])
			cube([rad*2,rad*2,rad],center=true);
	}
}
module result () {
	difference() {
		translate([0,0,24])
			shell(20,1);
		%3D_projection (30) 2D_shape();

	}
}

result();
// shell(20,3);

http://forum.openscad.org/file/n20356/sample-_scale_extrude.png

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