Doi: 10.1145/1610252.1610275

Designing Plush Toys
with a Computer

By Yuki Igarashi and Takeo Igarashi

abstract

We introduce Plushie, an interactive system that allows nonprofessional users to design their own original plush toys. To design a plush toy, one needs to construct an appropriate two-dimensional (2D) pattern. However, it is difficult for nonprofessional users to appropriately design a 2D pattern. Some recent systems automatically generate a 2D pattern for a given three-dimensional (3D) model, but constructing a 3D model is itself a challenge. Furthermore, an arbitrary 3D model cannot necessarily be realized as a real plush toy, and the final sewn result can be very different from the original 3D model. We avoid this mismatch by constructing appropriate 2D patterns and applying simple physical simulation to it on the fly during 3D modeling. In this way, the model on the screen is always a good approximation of the final sewn result, which makes the design process much more efficient. We use a sketching interface for 3D modeling and also provide various editing operations tailored for plush-toy design. Internally, the system constructs a 2D cloth pattern in such a way that the simulation result matches the user’s input stroke. We successfully demonstrated that nonprofessional users could design plush toys or balloon easily using Plushie.

1. intRoDuCtion

A computer can be a powerful tool for designing real-world objects. One can build a virtual three-dimensional (3D) model on a computer using computer-aided design (CAD) and use the model to run various simulations with computer-aided engineering (CAE) without the need to build or damage costly real objects. The benefits are evident in many areas from architecture to automobile design. However, these tools are mainly designed for professional users and are not particularly accessible to the ordinary person. The construction of a 3D model using a standard CAD system is tedious, and running a physical simulation using a standard CAE system requires a certain level of expertise.

Our goal is to bring the benefits of CAD and CAE to the hands of nonprofessional users including children. This article introduces our plush-toy design system, 18 Plushie, as an example of our efforts to achieve this goal. Plush toys are familiar objects in our daily lives, but their design is difficult. One must design an appropriate two-dimensional (2D) pattern to obtain a particular 3D shape, but the relationship between the two is nontrivial, and intensive experience and knowledge are required to achieve satisfactory results. As a result, most people simply buy ready-made plush toys and do not enjoy the design and construction of their own.

Figure 1. overview of Plushie system.

We have provided a way for people to design their own toys using a simple but powerful modeling tool that tightly integrates a sketching interface with physical simulation in the modeling process.

Plushie allows the user to design a plush toy from scratch by simple sketching operations. 18 The user first draws the desired silhouette, and the system automatically generates a 3D plush-toy model and corresponding 2D cloth pattern. The user can also edit the model, e.g., cut it or add a part, using a simple sketching interface, and the 3D model and 2D cloth pattern are automatically updated. The 3D model is the result of a physical simulation that mimics the inflation of the sewn 2D cloth patch. Therefore, the model on the screen is always a good estimate of the final sewn result (Figure 1). When we ran workshops in a museum to have novice users try our system, we observed that even children could design their own plush toys.

We first give an overview of sketching interfaces for 3D modeling and previous efforts to enable end users to design physical objects. We then describe the user interface and implementation of the Plushie system, followed by results and user experiences. Finally, we conclude the article with some discussion of future work.

2. SKEtChinG intERFaCES FoR 3D moDELinG The sketching interface part of Plushie is an evolution of the Teddy system we presented in 1999.11 That system allowed the user to create an interesting 3D model simply by sketching a silhouette of the target model (Figure 2, left). It was designed for the modeling of free-form rotund models, a task that is particularly difficult using standard modeling interfaces. Figure 3 shows an example of a modeling sequence using Teddy. The user’s strokes are shown in red, and everything else is inferred and drawn by the system. The user first draws

A previous version of this paper appeared in Proceedings of SIGGRAPH 2007/ACM Transactions on Graphics 26, 3 (2007), 45.