Figure 19. a plush toy and a balloon designed in our system.
Figure 22. Knitty system allows the user to design an original knitted
toy by simply drawing the desired silhouette.
they enjoyed the process. These toys were their own creations and one-of-a-kind designs. Participants also gave us
valuable feedback for future improvement. They wanted to
have some auxiliary functions such as the ability to design
symmetric parts and remove existing parts, but no one
complained about the quality of the visual simulation. A
perfectly accurate simulation is not necessary because
many small variations inevitably occur during the real sewing and stuffing process.
Figure 20. Example of texture changed. these models have many
Figure 21. Example of original plush toys designed and created by
children in the workshop.
children, approximately 10–14 years old, joined the workshop accompanied by their parents. We gave a brief tutorial at the beginning and had them design their own plush
toys using the system. It took about an hour for the design.
They then printed the designed pattern and sewed a real
3 h. Figure 21 shows a couple of plush toys created
in the workshop. Participants quickly learned how to use
the system and successfully designed the 3D models they
wanted, with some help from volunteers. Furthermore,
We introduced a plush-toy design system as an example of
our efforts to make CAD and CAE accessible to end users.
The system allows the user to design a plush toy quickly and
simply by combining simple sketching operations. The user
draws the desired silhouette on the canvas, and the system
automatically generates a 3D plush-toy model and a 2D cloth
pattern. The system runs a simple physical simulation in the
background so that the resulting 3D model is always a good
estimate of the final sewn result. The user can construct a
real plush toy by printing the pattern and sewing the resulting pieces together.
To demonstrate the effectiveness of the approach
even further, we also developed a system for the design of
13 A knitted toy is a toy made of knitted yarn
instead of cloth patches. One can construct a knitted
toy by knitting according to a specific knitting pattern,
but it is difficult to produce an appropriate knitting pattern for a desired 3D shape. The Knitty system allows the
user to design an original knitted toy by simply drawing the
desired silhouette (Figure 22). The system then generates a
3D knitted animal model and corresponding knitting diagram. We ran a workshop using this system and observed
that children could use it to design their own knitted
Interactive 3D modeling assisted by concurrent physical simulation can be a powerful tool in many other
application domains. For example, if one could run an
aerodynamic simulation during the interactive design
of a paper airplane model, the entire geometry could be
adjusted in an intelligent manner in response to the user’s
simple deformation operations to produce a model that
could actually fly. This kind of interaction would make it
easier for designers to pursue aesthetic goals while satisfying engineering constraints. Real-time simulation does
require high-performance computing resources, but some
meaningful support should be possible by carefully limiting the target task and designing appropriate interfaces as
shown in this paper. We hope that our work inspires more
work in this direction.