Day 127 - MakeyMakey Holder

Today this print-a-day project was featured on the MakerBot blog in the MakerBot Stories post Mathgrrl Makes a 3D print a Day, by Blake Eskin!

A year of 3D-printing-flavored making for me, and a new year of MakeyMakey-flavored making for my sister. Today we printed her jensa's MakeyMakey Gamepad case from Thingiverse/YouMagine, to go with her Thanxmas present:

Thingiverse link: http://www.thingiverse.com/make:60374
Download from YouMagine: https://www.youmagine.com/designs/makeymakey-gamepad

Settings: MakerWare .2mm/standard with supports to keep up the overhanging corners. We initially tried this on our usual .3mm/low setting but got a lot of loose diagonal threads on the flat base. Making the print finer solved the problem.

Day 126 - Dalek

I really hope my family isn't reading this blog, or they are finding out what all their Thanxmas presents are. To continue yesterday's theme, today we are printing guydebored's great Dalek model from Thingiverse.

Thingiverse link: http://www.thingiverse.com/make:60261

Settings: We printed the body on .3mm/low without raft or supports, and the weapons on .15mm/high with both raft and supports (in the horizontal position). It was a little fiddly to remove the supports but was worth it in the end. We had to trim the ends of the weapons a bit to fit into the holes on the Dalek. It looks really great since you imagine it all printed in one piece with the impossible overhangs that the weapons would cause. Wonderfully done model, thank you guydebored!

Day 125 - Tardi

My family is celebrating the holidays late with Thanxmas after the new year, and more presents are in order. Today, one large Tardis and two small, from Gossamer's wonderful Parametric Tardis model on Thingiverse:

Thingiverse link: http://www.thingiverse.com/make:60169

Settings: As usual, MakerWare .3mm/low with the small version printing in 37 minutes and the large one taking much longer. The Replicator 2 makes an interesting whistling noise during the print, as the fan blows into the hole carved into the Tardis model. Prints wonderfully without support or raft; this is a really well-done design.

Day 124 - Low-Poly Bear

What do you print for a person with minimalist tastes? I'm hoping a low-poly bear, like christophecaren's beautiful Bear model on Thingiverse.

Thingiverse link: http://www.thingiverse.com/make:60115

Settings: MakerWare .3mm/low, with raft and supports. I printed the model upside-down to minimize those supports and then had some minimal cleanup to do on the head and back after removing those supports.

Day 123 - "Ticket to Ride" card holder

A couple of days ago on Day 120, we printed some train trays for the excellent game Ticket to Ride. That was all well and good until the cards seemed all out of order and falling out of their giant tall stacks. So we printed a card holder for train cards, ticket cards, and used train cards. The logo for the game was put in the bottom with Tinkercad and Inkscape using the method outlined in Steps 4-6 on Day 109, with a picture from the internet as the starting point.

STL file: http://www.geekhaus.com/makerhome/day123_tickettoridecards.stl
Tinkercad link: https://tinkercad.com/things/0CO8dupbHOI-day-123-ticket-to-ride-card-holder
Thingiverse link: http://www.thingiverse.com/thing:214204

Settings: MakerWare .3mm/low on a Replicator 2 using the MakerBot "warm gray" filament that I seem to use for everything these days.

Stuff to change later: I forgot to put little bridges to attach the insides of the letters o, R, and d. Next time!

Day 122 - Menger Coaster Set, Part 2

Continuing from yesterday, here are the other four interesting slices of a Level 3 Menger Sponge:

STL files: http://www.geekhaus.com/makerhome/day122_mengercoaster5.stl (and 6 and 7 and 8)
Tinkercad link: https://tinkercad.com/things/auZS4Sd7vIe-day-122-menger-coaster-set-part-2
Thingiverse link: http://www.thingiverse.com/thing:213053

Settings: Like yesterday, we used Makerware .3mm/low,for a print time of about 30 minutes per coaster, with color swap just after 20 minutes or so.

Technical notes: See yesterday's post for hints about when to make the filament color swap. As you can see from the picture, the Replicator 2 is giving me some "stringy" behavior on the long traverses of black. I wonder if I could fix this with a temperature change or some other change? If anyone has any ideas please let me know.

UPDATE:  On Day 127 we figured out how to fix the "stringy" problem - change to .2mm/standard layer height. I imagine that change would also work for this model.

Day 121 - Menger Coaster Set, Part 1

Following up on Day 23's Menger-sponge-slice coaster, today we print four different slices of a Level 3 Menger Sponge.  There are four more interesting slices that we'll print tomorrow. These were constructed in Tinkercad after importing a Menger sponge that was created in Mathematica (although we could also have imported one built in Minecraft; see Day 108).

STL files: http://www.geekhaus.com/makerhome/day121_mengercoaster1.stl (and 2 and 3 and 4)
Tinkercad link: https://tinkercad.com/things/hTazkPXEpX8-day-121-menger-coaster-set-part-1
Thingiverse link: http://www.thingiverse.com/thing:213053

Settings: Makerware .3mm/low in about 30 minutes per coaster. The filament color swap takes place just after the 20 minute mark.

Technical notes: With the settings above, the first four layers will be black, but the last of those four will have outlines around the soon-to-be-white areas. Be sure not to stop too early; wait until you are sure the white part is being drawn before swapping the filament. Getting a little black under the white won't hurt, but getting any unwanted white over the black will be unacceptable.

Day 120 - "Ticket to Ride" trains tray

C's grandma gave us the game "Ticket to Ride" today, and it is great fun! The turns go by really quickly, making for a quick game that is fast-paced enough to hold everyone's attention even when it isn't their turn. However, each player has 45 trains to keep track of, which can get a bit messy. One of last year's Featured items on Thingiverse was a Ticket to Ride Locomotive Tray by princeofwands, which was updated and improved this year in HunterGreen's Ticket to Ride Rack design. However, both of those designs use a lot of plastic and take a long time to print. Today we designed a version in Tinkercad that uses far less material and prints in about half of the time, based loosely on the concept of our previous H-Tree Dish.

STL file: http://www.geekhaus.com/makerhome/day120_tickettoridetray.stl
Tinkercad link: https://tinkercad.com/things/cBtic9P91D4-day-120-ticket-to-ride-tray
Thingiverse link: http://www.thingiverse.com/thing:213031

Settings: MakerWare .3mm/low in just under an hour, without a raft. I added large "Helper Disks" (see under the MakerWare File menu, in the Examples category) to the corners to keep the model from peeling up, and cut off the disks after printing. Even with that I had to shift the model to the left of my build plate, since things always print funny for me in the bottom right corner for some reason, no matter how much re-leveling I do.  Maybe it is time to consider a glass build plate...

Technical notes: Now that I'm learning to use OpenSCAD I am starting to feel that things like this are a real pain to make in Tinkercad, especially if a lot of tweaking and re-aligning is involved. It's a lot like the difference between using LaTeX or Microsoft Word; as a LaTeX junkie I am definitely feeling the current pulling me a little bit more towards OpenSCAD every day.

Day 119 - DSi Stylus Holder

C recently finished saving up for his Nintendo DSi (see Day 18 and Day 19 from way back in September), and apparently it is necessary to have multiple styluses (styli?) so that you can change colors and lose them and things. Today we printed a small holder for them, designed in Tinkercad with their wonderful new "Extrusion" Shape Generator.

STL file: http://www.geekhaus.com/makerhome/day119_stylusholder.stl

Tinkercad link: https://tinkercad.com/things/0n7sUWBfAOE-day-119-dsi-stylus-holder

Thingiverse link: http://www.thingiverse.com/thing:212990

Settings: MakerWare custom profile to get a base and 2-layer sides but no top, in just a couple of minutes. Details on the profile are below.

Technical notes, Tinkercad flavor: The new "Extrusion" Shape Generator allows you to change the outline of a cylinder with a four-anchor Bezier curve. This is the first time it has been possible in Tinkercad to stretch a shape around by anchors and their tangent lines! Perhaps in the future we can get more handles and/or the ability to do this right on the workplane, add or remove handles, etc etc. This is a great step in the right direction for Tinkercad. Tinkercad also added a Ring Shape Generator and three types of Text, as they explain in this blog post.

Technical notes, MakerWare custom profile flavor: To get a solid base and just two layers around the outside of the shape, we started with the "Low PLA" profile in MakerWare 2.4.1.35 and changed the following lines in the profile:

"doRaft": false,
"infillDensity": 0,
 "roofThickness_disabled": 0,
 "roofLayerCount": 0,
 "floorThickness": 1.1,

Day 118 - Poly-Snaps Icosahedron

I always find the icosahedron the most difficult polyhedron to assemble with modular tiles. It is so close to spherical that the angles make assembly difficult; putting something together on one side tends to dislodge something on the other side. If you've ever assembled modular origami polyhedra then you know what I mean. It's possible with the compact Poly-Snaps we've been using over the past few posts, but the result it not that pretty. After much trial and error we finally found a lighter, larger style of Poly-Snaps that easily makes an icosahedron without hurting your hands or requiring pliers to put together, yet stays together well until you want it to come apart. The key to the stability is the fact that the tiles have five snaps on each side instead of three. For a dynamic classroom setting I think these lighter tiles would work very well.

Thingiverse link: http://www.thingiverse.com/make:58143

Settings: MakerWare .3mm/low.

Technical notes: These lighter, larger tiles were made with the Poly-Snap Customizer settings below.

Sides = 3
Snaps = 5
Side Length = 50
Thickness = 2
Border = 4
Clearance = .12
Lengthen = 1.5

Day 117 - Poly-Snaps Icosiodecahedron

Our fifth Poly-Snap example is the Icosidodecahedron, a semi-regular polyhedron with twenty triangles and twelve pentagons. It's sort of like a mini-Buckyball with triangles in place of the hexagons. Today's new model looks nicer and fits together better than our old snap-tile model from Day 89, and in addition you don't have to worry at all about which types of pentagon or triangle tiles you have along the way, since the Poly-Snaps all have the same snap configuration.

Thingiverse link: http://www.thingiverse.com/thing:208591

Settings: MakerWare .3mm/low in two batches (to get the two colors).

Technical notes: We used the default sturdy tile setting in the Customizer again, as below. If you have sensitive hands or want to easily take apart and put together the model over and over again, then I recommend either a lower Thickness or a higher Clearance. Test things out with a couple of tiles and see what you like best.

Sides = 3 and 5
Snaps = 3
Side Length = 25
Thickness = 3.5
Border = 3.5
Clearance = .17
Lengthen = .3 

Day 116 - Poly-Snaps Snub Cube

A "snub polyhedron" is a model obtained by adding triangles between the faces of another polyhedron. For example the Snub Cube below is like a cube whose six square faces have been exploded outward, with 32 triangles filling in the gaps:

Thingiverse link: http://www.thingiverse.com/thing:208591

Settings: MakerWare .3mm/low in two batches (to get the two colors).

Technical notes: Again we used the standard "compact" customizer settings. A pair of needle-nose pliers was needed to get the model together the first time, as the tiles don't have much clearance with these settings. (Actually for some of these we probably used Clearance = .15, since for some reason tiles with fewer sides seem to require less clearance.)

Sides = 3 and 4
Snaps = 3
Side Length = 25
Thickness = 3.5
Border = 3.5
Clearance = .17
Lengthen = .3

Day 115 - Poly-Snaps Truncated Octahedron

Today we "truncate" yesterday's octahedron. Truncating basically means that we slice off the corners of the object. The result here is semi-regular, meaning that each face is one of two regular polygons and that the same configuration of polygons surrounds each vertex. This Truncated Octahedron is composed of six squares (each the result of slicing off one of the six vertices of the octahedron) and eight hexagons (each the result of the original eight triangular faces of the octahedron getting sliced off at each corner). Compare to the model of this polyhedron we made in Day 88 with the old snap-tiles; notice here that on each side we have the same number of snaps, whereas in the older model we had various 2- and 3-snap configurations on the edges of the square and hexagon faces.

Thingiverse link: http://www.thingiverse.com/thing:208591

Settings: MakerWare .3mm/low in two batches (to get the two colors).

Technical notes: After yesterday's fiddly tiles we return to the compact, sturdy tiles from the day before, with the Customizer settings below.

Sides = 4 and 6
Snaps = 3
Side Length = 25
Thickness = 3.5
Border = 3.5
Clearance = .17
Lengthen = .3

Day 114 - Poly-Snaps Octahedron

Our second Poly-Snaps model is an Octahderon, with eight triangular faces. Compare with the Hinged Octahedron from Day 82, which is beautiful and prints in one piece, but has variable snap-numbers on its open edges and uses up a lot more material. Today's model makes use of the customizability of the Poly-Snaps, changing to very thin faces with large borders.

Thingiverse link: http://www.thingiverse.com/make:58146

Settings: MakerWare .3mm/low in almost no time at all.

Technical notes: Our goal here was to make something very light and easy to print quickly in large quantities, to make classroom use easier. However this particular choice of settings was not good for larger models with more sides. Some tinkering and possibly a redesign is still necessary to find a way to print very thin Poly-Snaps that actually stay snapped together.  But for the record, here were the Customizer settings we used for this model:

Sides = 3
Snaps = 3
Side Length = 25
Thickness = 1
Border = 5
Clearance = 0
Lengthen = 1.0

Day 113 - Poly-Snaps Truncated Tetrahedron

Over the next six days we'll be posting polyhedra that we assembled using our new Poly-Snaps on Thingiverse. Our previous polyhedral models were made from Snap Tiles which had either two or three snaps on each side. This new type of modular polyhedra-builder has the same number of snaps on each side and is customizable in Thingiverse Customizer. Today's print is a Truncated Tetrahedron composed of four triangles and four hexagons:

Thingiverse link: http://www.thingiverse.com/thing:208591

Settings: MakerWare .3mm/low in two batches (to get the two colors).

Technical notes: We used the following settings in the Thingiverse Customizer, which makes a sturdy, compact model that can be difficult to put together but stays together well even when tossed around.

Sides = 3 and 6
Snaps = 3
Side Length = 25
Thickness = 3.5
Border = 3.5
Clearance = .17
Lengthen = .3 

Technical notes, OpenSCAD flavor: This is one of my first OpenSCAD designs so it is kind of a hack, but here is the code I wrote to make the Poly-Snap tiles:

// mathgrrl polysnap tiles

////////////////////////////////////////////////////////////////
// PARAMETERS //////////////////////////////////////////////////

/* [Shape] */

// Choose the number of sides for the tile
sides = 5; // [3,4,5,6,7,8,9,10,11,12]

// Choose the number of snaps on each side
snaps = 3; // [2,3,4,5,6,7,8]

/* [Size] */

// Set the length of each side, in mm
side_length = 25; 

// Set the thickness of the tile, in mm
thickness = 3.5;

// Set the border thickness, in mm
border = 3.5;

/* [Adjust Fit] */

// Add extra space between snaps, in mm
clearance = .17;

// Add extra length to the snaps, in mm
lengthen = .3;

//radius depends on side length
radius = side_length/(2*sin(180/sides)); 

//inside radius depends on the border thickness
inside = radius-border/(cos(180/sides)); 

//width of each snap depends on number of snaps
snapwidth = radius*sin(180/sides)/snaps;

////////////////////////////////////////////////////////////////
// RENDERS /////////////////////////////////////////////////////

union(){
//make the polygon base
poly_maker();

//make the snaps
snap_maker();
}

////////////////////////////////////////////////////////////////
// MODULES /////////////////////////////////////////////////////

//build the polygon shape of the tile
//shape is made up of n=sides wedges that are rotated around
module poly_maker(){

//subtract the smaller polygon from the larger polygon
difference(){

//extrude to thicken the polygon
linear_extrude(height=thickness,center=true){ 

//rotate the wedge n=sides times at angle of 360/n each time
for(i=[0:sides]){

//rotation is around the z-axis [0,0,1]
rotate(i*360/sides,[0,0,1])

//make triangular wedge with angle based on number of sides
polygon(

//the three vertices of the triangle
points = [[0-.1,0-.1], //tweaks fix CGAL errors
[radius,0-.01],
[radius*cos(360/sides)-.01,radius*sin(360/sides)+.01]],

//the order to connect the three vertices above
paths = [[0,1,2]]
);
}
}
//extrude to thicken the center polygon that will be the hole
linear_extrude(height=thickness+2,center=true){ 

//rotate the wedge n=sides times at angle of 360/n each time
for(i=[0:sides]){

//rotation is around the z-axis [0,0,1]
rotate(i*360/sides,[0,0,1])

//make triangular wedge with angle based on number of sides
polygon(

//the three vertices of the triangle
points = [[0-.2,0-.2], //tweaks fix CGAL errors
[inside,0-.01],
[inside*cos(360/sides)-.01,inside*sin(360/sides)+.01]],

//the order to connect the three vertices above
paths = [[0,1,2]]
);
}
}
}
}

//build the snaps around the tile
//try the commands alone with i=1 and i=2 to see how this works
//remember to read from the bottom to the top to make sense of this
module snap_maker(){

//rotate the side of snaps n=sides times at angle of 360/n each time
for(i=[0:sides]){ 

//rotation is around the z-axis [0,0,1]
rotate(i*360/sides,[0,0,1])

//build snaps for first side at the origin and move into positions
for(i=[0:snaps-1]){

//read the rest of the commands from bottom to top
//translate the snap to the first side
translate([radius,0,-thickness/2]) 

//rotate the snap to correct angle for first side
rotate(180/sides) 

//for i^th snap translate 2*i snapwidths over from origin
translate([0,2*i*snapwidth,0]) 

//rounded box for snap made from a box and cylinder
union(){

//cube part of snap shape at the origin
cube([thickness/2+lengthen,snapwidth-clearance,thickness]);

//post at back of snap to avoid loose teeth
//shifted a bit right to avoid overhangs when sides=3
translate([-.5,.5,0])
cube([thickness/2,snapwidth-clearance-.5,thickness]);

//round part of snap shape at the origin
//move cylinder to the end of the box
translate([thickness/2+lengthen,
                   snapwidth-clearance,
                   thickness/2])
//rotate cylinder to match box orientation
rotate(90,[0,1,0]) 
rotate(90,[1,0,0]) 

//cylinder of the correct size to match box
cylinder(
r=thickness/2,
h=snapwidth-clearance,
$fn=16  //number of sides
);
}
}
}
} 

Update: These Poly-Snap triangle tiles were used by owens on Thingiverse to make a beautiful model of a toroidal polyhedron. So cool!

Day 112 - Tetris T's

I like the rounded and nicely-spaced design of 3DAndy's Pentominos on Thingiverse, but wanted to print some tetrominos instead, for math/puzzles (for example, polyomino packing problems) and for future Tetris-related art projects.  Since 3DAndy was nice enough to post his OpenSCAD code, it was easy to modify his pentomino-T into a tetromino-T.

STL file: http://www.geekhaus.com/makerhome/day112_tetrisT.stl
Thingiverse link: http://www.thingiverse.com/thing:212995

Settings: MakerWare .3mm/low, with 8 T's printing in 45 minutes and weighing only 16 grams. Tetris pieces is a great "stash-busting project" for those of you with lots of little scraps of filament that are too small for any normal print job.

Technical notes: Download the OpenSCAD code here or cut and paste from the below.

// mathgrrl tetrominos - example with Tetris "T"
// based directly on 3DAndy's pentominos

////////////////////////////////////////////////////////////
// PARAMETERS ////////////////////////////////////////////////////////////

//resolution
$fn=32;

//dimensions
length = 10;
radius = 1;
space = 0.2;

///////////////////////////////////////////////////////////////
// RENDERS ///////////////////////////////////////////////////////////////

//render an instance of the Tetris "T"
tetromino_T();

///////////////////////////////////////////////////////////////
// MODULES ///////////////////////////////////////////////////////////////

//define the blocks and connectors that make the Tetris "T"
module tetromino_T() {
union() {
// the blocks
translate([0,0,0]) 
myCube();
translate([length,0,0]) 
myCube();
translate([2*length,0,0]) 
myCube();
translate([length,length,0]) 
myCube();
// the connectors
translate([(0.5)*length,0,0]) 
myConnect();
translate([(1.5)*length,0,0]) 
myConnect();
translate([length,(0.5)*length,0]) 
myConnect();
}
}

//module for making the blocks
//eight spheres translated to the corners of the desired cube
//then convex hull of those spheres makes a rounded cube
module myCube() {
dist = length/2-radius-space;
hull() {
translate([dist,dist,dist]) 
sphere(r=radius);
translate([-dist,dist,dist]) 
sphere(r=radius);
translate([dist,-dist,dist])
sphere(r=radius);
translate([-dist,-dist,dist]) 
sphere(r=radius);
translate([dist,dist,-dist])
sphere(r=radius);
translate([-dist,dist,-dist]) 
sphere(r=radius);
translate([dist,-dist,-dist]) 
sphere(r=radius);
translate([-dist,-dist,-dist]) 
sphere(r=radius);
}
}

//smaller cubes used to connect adjacent blocks
//space between blocks is small enough that no support is needed to bridge the gap
//even though these hang in the air between the blocks they connect
module myConnect() {
translate([space+radius-length/2,space+radius-length/2,space+radius-length/2]) 
cube([length-2*space-2*radius,length-2*space-2*radius,length-2*space-2*radius]);
}

Day 111 - One MetroTech Center

This is a model of the building that houses the MakerBot Headquarters in Brooklyn, with a hole in it for a couple of pens or whatnot.  The basic building shape was downloaded from Trimble 3D Warehouse, then resized and converted to STL in Sketchup, with windows added in Tinkercad.

Happy holidays, MakerBot!

STL file: http://www.geekhaus.com/makerhome/day111_metrotech.stl
Tinkercad link: https://tinkercad.com/things/gQtw7tgKg06-day-111-one-metrotech-center-in-brooklyn
Thingiverse link: http://www.thingiverse.com/thing:208623

Settings: MakerWare .3mm/low in 3-4 hours.

Technical notes, short version: Get the model from Trimble, open and resize in Sketchup, clean up and add features in Sketchup or Tinkercad, and download the .stl for printing.

Technical notes, step-by-step version:

1. Download a Sketchup (.skp) model of a building from Google's Trimble 3D Warehouse.
2. Open the model in Sketchup. In order to look around with your mouse you'll have to first press "Orbit" or "Pan" from the button menu.
3. The building in this example had a flat ground-level piece attached to it. If this is true of your model then use the "Select" arrow to highlight that piece and delete it.
4. Sketchup is for buildings so the scale is HUGE in there. You'll have to shrink down the model a lot. One easy way to do this is to use the "Tape Measure" button, clicking first at one corner of the front of the building, then at the other. At the bottom of the window is a text box where you can enter the new length for the line segment you just selected with the tape measure. In the example model this length started as 214' 10 1/2" and I shrunk it down to 10'.  Now, I know that doesn't make sense because I can't print a 10-foot model, but shrinking it down to inches made it too small in Tinkercad for some reason. Fiddle around and see what works for you in the next steps.
5. Your model will now look really really tiny in Sketchup! You'll have to zoom in a lot if you want to find it, by using the scroll button on your mouse and pointing at the center of your desired zoom area. Hopefully your model is still near the origin. At this point you could modify your model in Sketchup but I think Tinkercad is easier so I'm going to do the rest over there.
6. Sketchup doesn't automatically know how to do export to STL, so you will have to install this free STL export plugin from Sketchup. If you have install problems then scroll through the comments on that site, where most problems you might encounter are discussed and solved. Once you have the plugin set up you should have an "Export STL" option under the "File" menu in Sketchup. Export your file.
7. Open this new .stl file in Tinkercad by using the "Import" tab at the top of the right menu column. Use inches as your unit of measurement, or at least give that a try and if it doesn't work then use millimeters. If your model is still too large or small you can change what you did in Step 4 with Sketchup, or you can just resize in Tinkercad. I have this weird feeling that extreme resizing in Tinkercad can cause problems, so if the size is way off then I would suggest going back to Sketchup to fix it.
8. Clean up your model in Tinkercad by using rectangular shapes to fill in or hole off things that you don't want. The model may be aligned one or two degrees away from the axes, which in particular could make it not sit flat on the Workplane. Use a rectangular hole to shave off the bottom of the building and make it flat, and then move the model back down to the Workplane.
9. If you want to add a hole to the building to make it a pen-holder or whatever then add a hole. I would advise doing that only after you have resized the building to the size that you will be printing at, so that you can control the size of the border around the hole accurately. 
10. Add windows or other features using small holes. It will go fairly quickly if you are good with the Align, Copy/Paste, Workplane, and Control-D tools. You don't want to be placing the windows of a skyscraper one at a time, so this would be a good time to go through some of the corresponding Tinkercad Lessons if you haven't already.
11. Download your finished .stl model and print! 

Day 110 - Rocking knot

Today's print is a knot with a special property: No matter how the knot sits on the table, it never touches the table in more than two places. This property makes the knot rock back and forth easily, and roll down even very shallow inclines. It's a fun thing to have on your desk, and it's the knot that I usually print at demos and talks.

STL file for thicker knot: http://www.geekhaus.com/makerhome/day110_rockingknot1.stl
STL file for thinner knot: http://www.geekhaus.com/makerhome/day110_rockingknot2.stl
Thingiverse link: http://www.thingiverse.com/thing:205464

Settings: Custom MakerWare profile to control the supports and how they attach to the models; see below for details. The knots in the picture were printed at 50%, 25%, and 15% scale from the STL files above.

Technical notes, math flavor: The thicker model was created in Mathematica using the following code:

a = .8 
 

b = Sqrt[1 - a^2]
   

(* a and b have to be numbers with a^2 + b^2 = 1 *) 

ParametricPlot3D[  

     {a*Cos[3 t]/(1 - b*Sin[2 t]),     

      a*Sin[3 t]/(1 - b*Sin[2 t]), 
  

      1.8*b*Cos[2 t]/(1 - b*Sin[2 t])}, 

     {t, 0, 2 Pi+.01}, 
 

     PlotStyle -> Tube[0.25, PlotPoints -> 24], 

     PlotRange -> All] 

Export["tritangentless_thick.stl", %]

The parametric equation in this code comes from Morton's paper Trefoil Knots Without Tritangent Planes, Bull. London Math Soc. 23 (1991), 78-80. Changing 0.25 to 0.15 in "Tube" creates the thinner model. The "+.01" at the end of the t-range is to make sure that the knot connects back to itself again when it closes the loop. If you take that part out then you will be able to pull apart the model in that spot, which is useful if you want to put the knot around something but not so useful if you don't want your model to look a little broken.

Technical notes, custom slicing profile flavor: The standard MakerWare profiles work very well for nearly everything I print, but for these knots those profiles leave too much support inside the knots that is difficult to remove.  Here's what I changed from the "PLA standard" profile:

• "roofThickness": 0.5,   (down from 0.8)
• "floorThickness": 0.5,   (down from 0.8)
• "sparseInfillPattern": "linear",  (instead of hexagonal, which shows through badly for these models when using translucent filament)
• "infillDensity": 0.2,   (up from 0.1, to make sure the knots are sturdy since they curve around a lot)
• "minSpurLength": 0.4,  (up from 0.34, but can't remember why i did this now – possibly because my knot models have bad mesh/slice problems sometimes and this was fixing the problem)
• "doSupport": true,
• "doSupportUnderBridges": true,
• "supportDensity": 0.1,   (down fro 0.2 – this is the part that helps the most for these models)
• "supportExtraDistance": 0.8,  (up from 0.5, since parts of the model can swing out far and need some extra support)
• "supportModelSpacing": 0.5,  (up from 0.4, to make the support further away from the model and thus easier to remove)

Action video! Note that the very slight incline of the closed laptop is enough to make these knots roll.

UDPATE: You can now order a print of this model from Shapeways at the new Geekhaus store.

Day 109 - Sharpie print

This design was inspired by DesignMakeTeach's excellent post Sharpie to 3D Print in 30 Minutes on his blog designmaketeach.com. Such a fantastic idea for introducing someone to 3D printing and for helping kids make simple prints! I wanted to take Shapeways out of the equation so I found a way to do the conversion step with my two favorite free and easy tools, Inkscape and Tinkercad; see the instructions below. The design we chose to work with was a picture of a house that C drew.  It was so great to see his drawing actually come to life and even stand up!

STL file: http://www.geekhaus.com/makerhome/day109_sharpieprint.stl
Tinkercad link: https://tinkercad.com/things/d1bVQxD8Aoh-day-109-sharpie-print
Thingiverse link: http://www.thingiverse.com/thing:204816

Settings: MakerWare .3mm/low with a Replicator 2 in about 30 minutes for the large one, and 10 minutes for the small one.

Technical notes, short version: Draw on paper with a Sharpie, take a photo, change to bitmap and save as an .svg file in Inkscape, load into Tinkercad, download as .stl and print.

Technical notes, long version: Since this project is so good for someone very new to 3D printing, in this long version I'm going to go through the instructions as if you haven't used Inkscape or Tinkercad very much before. But it's easy, I promise!

1. Draw a small picture on an index card with a Sharpie marker. Use thick lines and make sure that your entire picture is connected. (I had trouble explaining what this meant to kids until I had this example - now I can show them this picture and explain that the windows had to push out to touch the sides of the house to keep things connected.)  
2. Take a photo of the drawing with your camera or phone. I found that things work best if I don't use flash but I do make sure that the drawing is very well lit.
3. Open the photo in Inkscape and select the drawing with the arrow tool in the upper left. It will select the entire rectangle.
4. From the "Path" menu in Inkscape, select "Trace Bitmap". The default options work well, which means you should have "Brightness cutoff" selected and set to Threshold 0.450. Hit "Update" and you should see the drawing appear in the small Preview window. It might not look that great in the Preview window but that is okay.
5. Select "OK" and then close the "Trace Bitmap" window by clicking on the red button in the upper left. 
6. Save your file in .svg format. Make sure that you also change the extension of your file to .svg; this might not happen automatically.
7. Open a new model in Tinkercad and open the "Import" tab at the top of the right column menu. Select "Choose File" and go find the .svg file you made.
8. I suggest setting the Scale to 30% and height to 10mm. That will make the larger size of model that you see on the left in the photo above. Scaling to 15% and setting height at 5mm produced the smaller model in the photo.
9. If you want to use Tinkercad to modify or add to your drawing, now is the time to do that. For example, if you don't want to worry about the connectivity of the original drawing then you can add a back to the object at this step. DesignMakeTeach had a great suggestion for how to add a perfectly-shaped backing to your drawing on this Twitter post. Sure, it's obvious NOW, but it wasn't until I looked at that Tweet. 
10. Export your model from Tinkercad by selecting the "Design" dropdown menu and choosing "Download for 3D Printing", and then "STL" format. You'll have to close the "Download for 3D Printing" window after you do that; for some reason it does not close automatically.
11. Now you can use a 3D printer to print your .stl file. If your original drawing had a flat base then your model will probably stand up on its own!

UPDATE: jbreynoldsTRT used this method for a student's first design: 

Send us your pictures of printed Sharpie drawings and we'll post them here!

Day 108 - Minecraft castle

Minecraft is "The Last Starfighter" of 3D modeling and printing - a game that gets kids ready for the next industrial revolution by teaching them how to move, build, and think in a virtual 3D environment. Even better, you can load your 3D-modeled creations into your Minecraft worlds and also 3D-print your Minecraft creations in real life! Here is a simple castle that C and I made on a Printcraft server and exported to an .stl file we could 3D print (very detailed instructions below):

STL file: http://www.geekhaus.com/makerhome/day108_minecraftcastle.stl
Thingiverse link: http://www.thingiverse.com/thing:204613

Technical notes, Minecraft flavor: We used a lot of upside-down stairs to keep the amount of overhang to a minimum (thank you, Jeb!). The front archway stairs lead to an arrowslit that you can shoot arrows through. This slit is only the height of a slab - half of a block - and this small slit printed perfectly on the Replicator 2 with no supports!

Technical notes, 3D-printing flavor: MakerWare was unable to open the model as exported directly from Printcraft, so we had to do some tweaking in MeshLab. MeshLab is free but a bear to figure out, with dozens of incomprehensible menus. For this particular model the following sequence of menu options worked for us:

1. Cleaning and Repairing --> Remove Faces from Non Manifold Edges
2. Cleaning and Repairing --> Split Vertexes Incident on Non Manifold Faces
3. Repeat "Split Vertices" until the number of vertices shown at the bottom of the screen stops increasing. 
4. Remeshing, Simplification and Reconstruction --> Subdivision Surfaces: Catmull-Clark

The first three steps above remove some mesh problems, and the fourth step makes it so that MakerWare can open the file without crashing. Thank you to my student Ryan Moneymaker for showing me that you can accomplish a lot with MeshLab if you have the courage and patience to keep trying everything.

Here are detailed instructions for going between Minecraft and 3D printing:

*** TWO WAYS TO GO FROM MINECRAFT TO 3D-PRINTED OBJECT ***

Printcraft server ---> STL ---> Possible MeshLab repairs ---> 3D print

1. Open Minecraft and select Multiplayer to join a Printcraft server at us1.printcraft.org or eu1.printcraft.org. For more information see www.printcraft.org. 
2. Choose a plot on the Printcraft server and click the command block to "Claim" your plot.
3. Build your model! You won't be able to use chests, doors, or other decorative items; pretty much just blocks and stairs.  
4. Click the command block to output your model to an STL file.
5. Type "t" for chat and then click on the link; you'll be able to download your STL file from the website that is brought up.
6. Your model might be ready to print as-is! If you're using MakerWare then try to open the file; if it opens then use the Preview to see if the layers appear correctly. If things go sideways then try some MeshLab repairs such as the ones described earlier in this post.

Minecraft world with WorldEdit ---> STL ---> 3D print

1. From any Minecraft world, build your model! When you're done you can close Minecraft, since you'll be doing the rest of these steps from outside of Minecraft. You'll need to know where your Minecraft world file is kept on your machine; on a Mac it will be under YourUserName/Library/Application Support/minecraft/saves. 
2. Download and install Mineways.
3. Mineways provides two video tutorials (here and here) to help you get started. Basically you'll open your Minecraft world in Mineways and then from a map view you'll choose the area that you want to select as your model. You'll also need to know how high/low to select for your area (the y-coordinate), so make a note of that before you leave your Minecraft world. 
4. Open and print your STL model! (This is the method we used for the Videogame Dice in Day 12.)

*** TWO WAYS TO GO FROM 3D MODEL TO MINECRAFT WORLD ***

STL ---> Tinkercad ---> MCEdit ---> Minecraft

1. Make a 3D model however you like (or even scan/Digitize one!) and save as an STL file.
2. Get a free account at Tinkercad and import your model using the "Import" menu option at the top of the right column. (Unless you used Tinkercad to create your model, in which case you already have it there!)
3. From the Tinkercad "Design" menu, select "Download for Minecraft". (I know, right? How awesome is it that they actually have this option built into their menu? Thank you, Tinkercad!) This will export your 3D design as a .schematic file.
4. Download MCEdit and use it to import this .schematic file to the place you want it to be in your Minecraft world. Tinkercad has a great blog post describing how to do this.

STL ---> Tinkercad ---> WorldEdit ---> Minecraft

1. Follow steps 1-3 above to get a .schematic file for your 3D model. 
2. For this method you have to have WorldEdit, either installed on a Multiplayer server or on Singleplayer as part of Single Player Commands. Put your .schematic file where WorldEdit can find it; on a server installation this will be somewhere like Minecraft/plugins/WorldEdit/schematics.
3. From within your Minecraft world, use //schematic load yourfilename to load your .schematic file into the WorldEdit clipboard, move to where you want the model to be, and then //paste the model into your world. You may have to //rotate or move around to find the positioning you want; remember you can always //undo to try again!
4. Enjoy having crazy models in your Minecraft world - like the mathematical knot shown below (see Day 9, Day 11, Day 66, and Day 67 for knot models).

Day 107 - SEGA Sonic cartridge sleeves

We love Sonic 2 on the SEGA Genesis, and we've recently been enjoying the whole series all over again with our son. Our ancient cartridges don't have protective sleeves, so we printed some custom ones! Designed in Tinkercad with some help from Inkscape and the internet (specifically, the nice .svg images on Wikipedia here and here).

STL file: http://www.geekhaus.com/makerhome/day107_sonicsleeves.stl
Tinkercad link: https://tinkercad.com/things/8BEl67GPJBF-day-107-sega-genesis-cartridge-case
Thingiverse link: http://www.thingiverse.com/thing:203998

Settings: MakerWare .3mm/low in about 37 minutes on the Replicator 2.

Technical notes: We had hoped that since we found the "SEGA" and "Sonic" logos in .svg format we would be able to import them into Tinkercad without problems, but unfortunately the importing process made the insides of the letters all filled in, rendering the words illegible. To fix this we opened the files in Inkscape and did the following:

1. Select image with the arrow tool.
2. From the "Path" menu select "Object to Path".
3. Using the node-arrow tool (under the usual arrow tool), select and delete parts of the image that are not desired. In this case there was an outline around the letters that needed to be deleted before exporting for Tinkercad. The "delete" key did not work for us, but using "Cut" under the "Edit" window did. This is not needed for all images but it was needed for both of the ones in this example.
4. Save the image in .svg format.
5. Import the image into Tinkercad using the "Import" tab at the top of the right column menu. 

Day 106 - Filament Shelf Clip

I keep my filament on an old curtain rod over a shelf, and the rolls that are far away from the printer don't unroll correctly. This shelf clip fixes the problem. The open loop design allows it to open a bit to fit over the shelf with a small dot of poster-tack-gum underneath to keep it from sliding to the side. Made in Tinkercad.

STL file: http://www.geekhaus.com/makerhome/day106_filamentshelfclip.stl
Tinkercad link: https://tinkercad.com/things/byqokD7ZUIX-day-106-shelf-clip-fliament-guide
Thingiverse link: http://www.thingiverse.com/thing:203978

Settings: MakerWare .3mm/low on a Replicator 2 in 20 minutes.

Day 105 - Bow Box

Tired. Need simple. Something that just works. How about muddtt's Christmas Gift Box on Thingiverse?

Thingiverse link: http://www.thingiverse.com/make:56796

Settings: MakerWare .3mm/low with the base and the bow in one print and the top in another.

Stuff to change: I really love siesauers' Make of this model where they printed everything in translucent filament and colored the bow and ribbon with Sharpie afterwards. It looks great to have the bow and ribbon the same color and all around the box. Next time!