IEEE Robotics & Automation Magazine - September 2020 - 23

of the microfigurines and also the ability to position them
with micrometric precision in front of an imager. The microfigurines were printed with a two-photon 3D printer available
at the Université Libre de Bruxelles, the resolution of which is
about 1 μm. At this scale, the best way to visualize 3D objects
is with an SEM operating in a vacuum chamber. The microfigurines were metallized to be visible in the SEM. To position
the figurines in front of the imager, high-precision miniaturized robots working in a vacuum chamber and developed at
the Franche-Comté Electronics Mechanics Thermal Science
and Optics-Sciences and Technologies (FEMTO-ST) Institute were used.
Two other stop-motion films at the micronanoscale have
been produced in recent years, and each qualifies for a different category in Guinness World Records [5], [6]. A Boy and His
Atom, a film produced by IBM, was performed in a scanning
tunneling microscope that enabled the visualization of single
atoms on a substrate [7]. This 1-min black-and-white film
shows a boy playing with a ball, which is a monoxide molecule.
The character is significantly smaller (a few nanometers in
height) than the figurines in Stardust Odyssey (300 µm), but the
boy is a planar drawing and not a real 3D figurine.
The second world record is for the smallest 3D figurine in
a stop-motion animation. The record was initially established
with Dot, a film produced by Nokia [8]. In this 2-min film
shot with a Nokia N8 phone, a tiny (9-mm) 3D figure of a
girl discovers the magical millimeter-scale world while flying
on a bee. The 80-s film presented in this article is the new
holder of this second Guinness world record [5], with the
Stardust Odyssey figurine being 30 times smaller than the figurine in Dot [8]. Note, however, that Stardust Odyssey is a
black-and-white film, whereas Dot is in color.
Each key technology required ad hoc developments to
build the film. The multidisciplinary technological challenges
and methodologies are described in the following sections. In
other words, Stardust Odyssey's costume designer, makeup
artist, robotic cameraman, and filmmaker are presented in
the article.
The Costume Designer: A Two-Photon 3D Printer
This project required a production technique compliant with
the most important requirements: the size of the figurine and
its details, 3D geometrical complexity, and compatibility with
the imaging process (i.e., the SEM). First, the figurine height
is about 300 µm, and even smaller details must be included to
provide some feeling of emotions, conveyed through the eyes,
face, or fingers of our microhero. Second, the microfigurines
are not only small-only three times taller than the diameter
of a human hair; they also include high 3D geometrical complexity to reproduce the human aspect of the character. Third,
the microfigurines must be produced in a conductive material
to avoid saturation by electron accumulation on insulative
materials during the imaging process (see the section "The
Robotic Camera Operator: A Microrobot in an SEM").
Focused ion beam (FIB) systems could be used to sculpt
metallic materials at the required scale but would not be

suitable with the geometrical overhangs. Alternatively, we
opted for the two-photon lithography technique, a kind of
3D printer polymerizing submicron voxels of polymer resin
with a laser [9]. The resolution and geometrical versatility
of this digital printing process make this technique the
standard for printing complex geometrical parts at the
micron scale.
The third criterion (conductive material) was circumvented by postprocessing the figurine with a metallic coating.
The optimization of all printing parameters was really challenging, allowing the researchers to push forward the frontiers of their equipment.
The Basic Principles of the Printer
and Ad Hoc Developments for the Film
As mentioned, 3D printing by two-photon lithography
enables the production of complex 3D structures with submillimeter dimensions and submicrometer details. The
objects obtained allow researchers to explore phenomena at
microscopic scale in multiple fields: surface texturing, replication of bio-inspired structures, microrobotics, molecular biology, microfluidic application, and so on. At the Université
Libre de Bruxelles, the researchers of the Transfers, Interfaces,
and Processes (TIPs) team study microfluidic phenomena,
that is, the properties of fluid flow at very small scale.

Figure 1. The Stardust Odyssey official poster.

SEPTEMBER 2020

IEEE ROBOTICS & AUTOMATION MAGAZINE

IEEE Robotics & Automation Magazine - September 2020

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