Preparing a “Blobby” Object for Printing with Shapeways

blender_gen_shell.py

wallScale = 0.975;

print('Generate inner shell');
bpy.ops.object.duplicate();
innerShell = bpy.data.objects['0431630057 Sphere Tri 5.001'];
bpy.ops.transform.resize(value=(wallScale,wallScale,wallScale));

print('Subtract inner from outer shell');
bpy.context.scene.objects.active = outerShell;
bpy.ops.object.modifier_add(type='BOOLEAN');
outerShell.modifiers[0].operation = 'DIFFERENCE';
outerShell.modifiers[0].object = innerShell;
bpy.ops.object.modifier_apply(apply_as='DATA',modifier='Boolean');
innerShell.select = True;
bpy.context.scene.objects.active = innerShell;
bpy.ops.object.delete();

blender_import.py

import bpy
from sys import platform as _platform

print('Delete existing meshes');
bpy.ops.object.select_by_type(type='MESH');
bpy.ops.object.delete();

print('Load outer shell');
bpy.ops.import_mesh.stl(filepath='0431630057_sphere_tri_5.stl');
outerShell = bpy.data.objects['0431630057 Sphere Tri 5'];

print('Ensure normals face out');
bpy.context.scene.objects.active = outerShell;
bpy.ops.object.mode_set(mode='EDIT');
bpy.ops.mesh.select_all(action='SELECT');
bpy.ops.mesh.normals_make_consistent(inside=False);
bpy.ops.object.editmode_toggle();

create_lattice_of_spheres.py

import bpy
import math
from mathutils import Vector

def drange(start, stop, step):
    r = start
    while r <= stop:
        yield r
        r += step

r = 0.25;
rSphere = r*0.975;
sphereSubdivisions = 4;

print('Delete existing meshes');
bpy.ops.object.select_by_type(type='MESH');
bpy.ops.object.delete();

context = bpy.context

# Cut out the spherical grid
for x in drange(-0.75/r, 0.75/r, 1):
    for y in drange(-0.75/r, 0.75/r, 1):
        for z in drange(-0.75/r, 0.75/r, 1):
            print(x,y,z);
            
            origin = (0,0,0);
            moveTo = (x*2*r - (y%2*r) - (z%2*r),
                      r + (math.sqrt(3)*r*y) + (z%2*r)/2,
                      r + (math.sqrt(6)*2/3*r*z));
            bpy.ops.mesh.primitive_ico_sphere_add(location=origin,size=rSphere,subdivisions=sphereSubdivisions);
            obj = context.active_object;
            obj.location += Vector(moveTo);
        
            sphereToDelete = bpy.data.objects['Icosphere'];

export_mesh.py

print('Export the mesh');
bpy.ops.object.select_by_type(type='MESH');
bpy.ops.export_mesh.stl(filepath='holyMesh.stl');

gen_sphere_cube

r = 0.05;
rSphere = r*0.975;

for ( x = [-0.75/r:0.75/r]) {
   for ( y = [-0.75/r:0.75/r]) {
      for ( z = [-0.75/r:0.75/r]) {
         translate( [x*2*r - (y%2*r) - (z%2*r),
                     r+ sqrt(3)*r*y + (z%2*r)/2,
                     r + sqrt(6)*2/3*r*z] )
         sphere(rSphere, $fn=50, center = false);
      }
   }
}

gen_sphere_cube_diff

r = 0.05;
rSphere = r*0.975;
wallScale = 0.975;
difference() {
   difference() {
      % import("0431630057_sphere_tri_5.stl");
      scale([wallScale,wallScale,wallScale]) import("0431630057_sphere_tri_5.stl");
   }

   % for ( x = [-0.75/r:0.75/r]) {
      for ( y = [-0.75/r:0.75/r]) {
         for ( z = [-0.75/r:0.75/r]) {
            translate( [x*2*r - (y%2*r) - (z%2*r),
                        r+ sqrt(3)*r*y + (z%2*r)/2,
                        r + sqrt(6)*2/3*r*z] )
            sphere(rSphere, $fn=50, center = false);
         }
      }
   }
}

gen_sphere_cube_diff.py

import bpy
from sys import platform as _platform
import math
from mathutils import Vector

def drange(start, stop, step):
    r = start
    while r <= stop:
        yield r
        r += step

r = 0.25;
rSphere = r*0.975;
wallScale = 0.975;
sphereSubdivisions = 4;

print('Delete existing meshes');
bpy.ops.object.select_by_type(type='MESH');
bpy.ops.object.delete();

print('Load outer shell');
bpy.ops.import_mesh.stl(filepath='0431630057_sphere_tri_5.stl');
outerShell = bpy.data.objects['0431630057 Sphere Tri 5'];

print('Ensure normals face out');
bpy.context.scene.objects.active = outerShell;
bpy.ops.object.mode_set(mode='EDIT');
bpy.ops.mesh.select_all(action='SELECT');
bpy.ops.mesh.normals_make_consistent(inside=False);
bpy.ops.object.editmode_toggle();

print('Generate inner shell');
bpy.ops.object.duplicate();
innerShell = bpy.data.objects['0431630057 Sphere Tri 5.001'];
bpy.ops.transform.resize(value=(wallScale,wallScale,wallScale));

print('Subtract inner from outer shell');
bpy.context.scene.objects.active = outerShell;
bpy.ops.object.modifier_add(type='BOOLEAN');
outerShell.modifiers[0].operation = 'DIFFERENCE';
outerShell.modifiers[0].object = innerShell;
bpy.ops.object.modifier_apply(apply_as='DATA',modifier='Boolean');
innerShell.select = True;
bpy.context.scene.objects.active = innerShell;
bpy.ops.object.delete();

context = bpy.context

# Cut out the spherical grid
for x in drange(-0.75/r, 0.75/r, 1):
    for y in drange(-0.75/r, 0.75/r, 1):
        for z in drange(-0.75/r, 0.75/r, 1):
            print(x,y,z);
            
            origin = (0,0,0);
            moveTo = (x*2*r - (y%2*r) - (z%2*r),
                      r + (math.sqrt(3)*r*y) + (z%2*r)/2,
                      r + (math.sqrt(6)*2/3*r*z));
            bpy.ops.mesh.primitive_ico_sphere_add(location=origin,size=rSphere,subdivisions=sphereSubdivisions);
            obj = context.active_object;
            obj.location += Vector(moveTo);
        
            sphereToDelete = bpy.data.objects['Icosphere'];
            
            bpy.context.scene.objects.active = outerShell;
            bpy.ops.object.modifier_add(type='BOOLEAN');
            outerShell.modifiers[0].operation = 'DIFFERENCE';
            outerShell.modifiers[0].object = sphereToDelete;
            bpy.ops.object.modifier_apply(apply_as='DATA',modifier='Boolean');
            sphereToDelete.select = True;
            bpy.context.scene.objects.active = sphereToDelete;
            bpy.ops.object.delete();

illustrate_difference

wallScale = 0.975;
difference() {
  % import("0431630057_sphere_tri_5.stl");
  scale([wallScale, wallScale, wallScale]) import("0431630057_sphere_tri_5.stl");
}

import_to_openscad

import("0431630057_sphere_tri_5.stl");