by Erik Es - Amsterdam, July 3, 2018
There are several ways to create 3D prints that
have one or more loose parts locked inside of
them. One easy way is what I call "insertion
printing". This can be done by printing a hollow
object. During printing the top will still be open
so it is pretty easy to drop something inside it.
That's how I made this "Marble Cage",
for instance:
You can pause the printer at some point to insert
an object, but that will almost certainly cause a
visible seam in the print, especially if it has very
thin walls. So it is much better to insert things
without pausing the printer (although that is a bit
more tricky, especially with small prints).

Timing is essential. If you insert the object too
early, the print head starts hitting the object that
was placed inside, ruining the print. If you get
distracted, by the time you look at the printer
again the top might suddenly be closing up -
too late... After a few of those events I realised
that a timer is very useful.

One of my favourite designs incorporating
insertion printing is one I made in 2013:

Some people have strange hobbys. For centuries
there have been oddballs that kept themselves
busy by putting ships into bottles. I have always
found their work quite fascinating.

A ship in a bottle is a visual conundrum - it
seems impossible to get that ship into that bottle.
Many people assume that it is done by forming/
shaping the bottle around the ship using some
kind of glassblowers trick. Not so.
SPOILER ALERT: If you don't want to know how it
is done, skip the next bit.

The model ship is (mostly) constructed outside
the bottle. To get it into the bottle, it is made in
such a way that the masts can be raised by
pulling on some cleverly placed strings.
The ship, masts down, is inserted through the
opening of the bottle (which is usually relatively
wide). The strings are then pulled to deploy
masts and sails. Hey presto !

With special instruments the strings are glued or
knotted to the model. Then the loose ends are
cut to hide the evidence of how it's done.
Sometimes extra ornaments (like cannons and
such) are added to the ship, and often some kind
of sea is added to the scene as well, using
plaster or wax or such. This all requires special
tools, which these shipbuilders mostly make
themselves. Wonderful people.

So I decided to create a
3D printed ship-in-a-bottle.

First I designed a bottle. I gave the bottle one flat
side so it can be placed on its side.

For those who are wondering: yes, the bottle is
designed as a solid shape. Turning it into a
hollow bottle is done by adjusting the appropriate
settings in the software that controls the printer.

Then I made the ship. I decided that it would be
nice to use a fairly modern design instead of an
old-fashioned sailship. I also realised that it
would need to be a rather bold design, as any
small detail would not be visible through the
printed bottle.

So I modeled the ship like this:

There is another reason I made the ship like this.
More about that later.

I print the ship first (of course), then I print the
bottle. Here's the bottle being printed just before
the ship is inserted:

As the bottle starts to get thinner it is time to
insert the ship. It just about fits past the print
head, but only at some point during the rotating
movement of the head. I have to dump it in
quickly otherwise the print head catches it,
resulting in a ship wreck.
When I get it right it looks like this:

When the bottle is done the ship is locked inside.
Hey presto !
I decided not to make any special instruments to
glue the ship down inside the bottle. The fact that
it rattles around inside seems more intriguing...
and it saves a lot of work.

The lens effect of the layers in the bottle (single
wall, 0.4 mm thick, layer height 0.2 mm) does
blur the view inside, as you can see.

However, there turned out to be an unexpected
effect: viewed from certain angles, the (blurry)
ship seems to be hovering IN FRONT of the
bottle, like a hologram. Quite freaky.
Pity I can't show you here...

The ship-in-a-bottle is just one of the cool 3D
prints that can be found at Printed In Space.

More about ships and bottles in the next blog:


In past centuries ship-in-a-bottle makers had few
possibilities to connect with fellow enthusiasts.
With the advent of internet these craftsmen have
now connected globally, showing their fabulous
creations to each other and the rest of the world.
To see some amazing pieces, I strongly
recommend a browse through this website:

But DO come back afterwards to read part 2 of
this blog: