In post #94 :

3D part design with Inkscape and OpenSCAD #94: Using minkowski() to hollow out complex shapes.
I recently set out to design a pair of shoes with Inkscape and OpenSCAD and wanted a simple way to make a shell out of a complex object and make it so that the walls would be a consistent width that was adjustable and it turns out that using minkowski
infinityplays.comBob

I made a module to hollow out the center of complex objects using minkowski() and it works really well but I wanted to add some features like being able to see the inside "hollowed" out area and being able to adjust it for different shapes, it turns out it was pretty easy to do this.

here is the updated code:

/*[HollowOutV2]*/
Path_to_STL_File=".stl";
UseSphere=false;
UseCube=false;
rounding=24;//[3:1:40]
thickness=.5;//[.01:.01:40]
/*[Outside]*/
Resize_outside=100;//[.10:.01:400]
Move_outsideX=0;//[-100:.01:100]
Move_outsideY=0;//[-100:.01:100]
Move_outsideZ=1;//[-100:.01:100]

/*[Inside]*/
Resize_inside=90;//[.10:.01:400]
Move_insideX=4;//[-100:.01:100]
Move_insideY=0;//[-100:.01:100]
Move_insideZ=1;//[-100:.01:100]

/*[Hidden]*/
$fa=$preview? 2:.1;;
$fs=$preview?.1:.01;;

module HollowOutV2(){
difference() {
minkowski() {
translate([Move_outsideX,Move_outsideY,Move_outsideZ])
resize([Resize_outside,0,0],auto=true)
import(Path_to_STL_File);
if(UseSphere)
sphere(r=thickness,$fn=rounding,true);
if(UseCube)
cube(-thickness,true);
}
translate([Move_insideX,Move_insideY,Move_insideZ])
resize([Resize_inside,0,0],auto=true)
import(Path_to_STL_File);
}}

color("dodgerblue",.3)
resize([Resize_outside,0,0],auto=true)
HollowOutV2();

I added the ability to move and resize the outer and inner parts individually, and added transparency so you can see the inner part so it can be adjusted.

What's cool about this is now I can make the inside the perfect shape of my foot and the outside the shape of a normal shoe. I can also add additional layers so I can put a cushion zone in between the inner and outer layers, moving the shock absorbing part of the shoe to the middle, which should make these super comfortable.

I know the shoe looks pretty plain right now but stay tuned for more updates, there are going to be quite a few.