Category Archives: Art

3D Printing: MSLA printing Triply Periodic Minimal Surfaces (TPMS) – Gallery


  • 2023/03/12: starting write-up, and published

20mm cubes of several Triply Periodic Minimal Surfaces (TPMS) as explored at Generative Parametric Infill Geometries printed with MSLA (Anycubic Photon Mono 4K) at 35 μm XY, 50 μm Z:

Most of the cubes were printed without support, the cylindrical and spherical projections required supports.



3D Modeling: Random Snapshots 2020

3D Modeling: Elegant Pieces in OpenSCAD with rcube(), rcylinder() and chainhull()


  • 2020/12/31: rcube() extended, RCUBE_FLAT{BOTTOM, TOP, FRONT, BACK, LEFT, RIGHT} support added, rcylinder() with RCYLINDER_FLAT{TOP, BOTTOM}
  • 2020/12/30: rcube() source code extended, support RCUBE_FLATX, RCUBE_FLATY, RCUBE_FLATZ
  • 2020/12/28: inital post

While working on Ashtar D (Classic XY) I looked at some pieces I rushed to design with cube() and hull() and they didn’t appeal to me – yes, it kind of hurt my eyes.

A while back I coded a simple rcube([x,y,z],r) which takes r as a radius for the edges, internally it’s an OpenSCAD module which uses 8 spheres and hulls them together, providing round edges; but I hesitated to actually use it in my designs – until now. Further I thought, let’s do the same with cylinder() using rcylinder(d=10,h=5,r=1) providing round edges by using two torii and hull them together.

These two new functions, rcube([x,y,z],r) and rcylinder(h,d,r) allow to create more organic and elegant pieces, see for yourself:

From Bulky To Elegance

The position of the Y pulley mount is given, a bit of an X- & Y-offset to ensure printable area is not sacrificed for the Y carriage:

Using Chained Hulls

And another example . . . replacing hull() with chainhull():

The final version is composed by only 3 pieces chain hulled together:

difference() {
   chainhull() {
      translate([0,0,-20]) rcube(...);
      translate([...,-60]) rcube([5,20,50],2); // 2020 mount plate
   rcube(...);     // pulley cutout

rcube() & rcylinder()

translate([5,0,0]) rcube(0.75);
translate([10,0,0]) rcube([2,1,1],0.2);

translate([0,2,0]) rcube([2,1,1],0.2,false);
translate([5,2,0]) rcube([2,1,1],0.2,true);

translate([0,4,0]) rcube([2,1,1],0.2,RCUBE_FLATX);
translate([5,4,0]) rcube([2,1,1],0.2,RCUBE_FLATY);
translate([10,4,0]) rcube([2,1,1],0.2,RCUBE_FLATZ);

translate([0,6,0]) rcube([2,1,1],0.2,RCUBE_FLATBOTTOM);
translate([5,6,0]) rcube([2,1,1],0.2,RCUBE_FLATTOP);

translate([0,8,0]) rcube([2,1,1],0.2,RCUBE_FLATFRONT);
translate([5,8,0]) rcube([2,1,1],0.2,RCUBE_FLATBACK);

translate([0,10,0]) rcube([2,1,1],0.2,RCUBE_FLATLEFT);
translate([5,10,0]) rcube([2,1,1],0.2,RCUBE_FLATRIGHT);

translate([0+1,14,0]) rcylinder(3,1.5,0.2);
translate([3+1,14,0]) rcylinder(3,1.5,0.2,false);
translate([6+1,14,0]) rcylinder(3,1.5,0.2,RCYLINDER_FLATBOTTOM);
translate([9+1,14,0]) rcylinder(3,1.5,0.2,RCYLINDER_FLATTOP);

The library code (I might later release it as a separate library):

// Title: rcube(), rcylinder() & torus()
// Author: Rene K. Mueller
// License: MIT License 2020
// Version: 0.0.2

RCUBE_FLATX = [false,true,true];
RCUBE_FLATY = [true,false,true];
RCUBE_FLATZ = [true,true,false];
RCUBE_FLATBOTTOM = [false,false,false,false,true,true,true,true];
RCUBE_FLATTOP = [true,true,true,true,false,false,false,false];
RCUBE_FLATFRONT = [false,false,true,true,false,false,true,true];
RCUBE_FLATBACK = [true,true,false,false,true,true,false,false];
RCUBE_FLATLEFT = [false,true,true,false,false,true,true,false];
RCUBE_FLATRIGHT = [true,false,false,true,true,false,false,true];

module rcube(a=1,r=0.1,rd=[true,true,true],center=false,$fn=32) {
    else {
       x = len(a) ? a[0] : a;
       y = len(a) ? a[1] : a;
       z = len(a) ? a[2] : a;
       rd = len(rd) ? rd : [rd,rd,rd];

          if((len(rd)==3 && rd[0] && rd[1] && rd[2]) || (len(a)==0 && rd)) // rd=[true,true,true] or true
             hull() {
                translate([r,r,r]) sphere(r);
                translate([x-r,r,r]) sphere(r);
                translate([x-r,y-r,r]) sphere(r);
                translate([r,y-r,r]) sphere(r);
                translate([r,r,z-r]) sphere(r);
                translate([x-r,r,z-r]) sphere(r);
                translate([x-r,y-r,z-r]) sphere(r);
                translate([r,y-r,z-r]) sphere(r);
          else                                                        // anything else
             hull() {
                translate([r,r,r]) rcube_prim(r,rd,0);
                translate([x-r,r,r]) rcube_prim(r,rd,1);
                translate([x-r,y-r,r]) rcube_prim(r,rd,2);
                translate([r,y-r,r]) rcube_prim(r,rd,3);
                translate([r,r,z-r]) rcube_prim(r,rd,4);
                translate([x-r,r,z-r]) rcube_prim(r,rd,5);
                translate([x-r,y-r,z-r]) rcube_prim(r,rd,6);
                translate([r,y-r,z-r]) rcube_prim(r,rd,7);

module rcube_prim(r,rd,i) {
    a = len(rd);
    if(a<=3) {
       if(a && rd[0] && rd[1] && rd[2]) 
       else if(a && rd[0] && rd[1])
          translate([0,0,-r]) cylinder(r=r,h=r*2);
       else if(a && rd[1] && rd[2])
          translate([-r,0,0]) rotate([0,90,0]) cylinder(r=r,h=r*2);
       else if(a && rd[0] && rd[2])
          translate([0,-r,0]) rotate([-90,0,0]) cylinder(r=r,h=r*2);
          translate([-r,-r,-r]) cube(r*2);
    } else 
          translate([-r,-r,-r]) cube(r*2);

RCYLINDER_FLATTOP = [true,false];

module rcylinder(h=2,d=1,r=0.1,rd=[true,true],$fn=40) {
       hull() { 
             if(len(rd) && rd[0]) torus(do=d,di=r*2); else translate([0,0,-r]) cylinder(d=d,h=r);          
             if(len(rd) && rd[1]) torus(do=d,di=r*2); else cylinder(d=d,h=r);

 module torus(do=2,di=0.1,a=360) {
    rotate_extrude(convexity=10,angle=a) {
       translate([do/2-di/2,0,0]) circle(d=di,$fn=20);


module chainhull() {
       hull() {

There is one drawback using chainhull() { } as you can’t use conditional if else with { } within as it combines them as a group and becomes a child structure and so it will act as hull(), so you only can list non-conditional pieces within chainhull() as of OpenSCAD 2019.05, perhaps at a later time this limit vanishes.

That’s it.