Yuki Igarashi

Implementing As-Rigid-As-Possible Shape Manipulation and Surface Flattening

This article provides a description of an as-rigid-as-possible shape manipulation implementation that is clearer and easier to understand than the original. While the original paper used triangle-based representation, we use edgebased representation to simplify the coding. We also extend the original algorithm to allow the user to place handles on arbitrary positions of the mesh. In addition, we show that the same algorithm can be used for surface flattening with quality and performance comparable to popular flattening methods.

Knitting a 3D Model

A knitted animal is made of a closed surface consisting of several knitted patches knitted out of yarn and stuffed with cotton ( Fig. 1 ). We introduce a system to create a knitting pattern from a given 3D surface model (mainly designed for rotund animal models). A knitting pattern is an instructional diagram describing how to knit yarn to obtain a desired shape. Since the creation of knitting patterns requires special skill, this is difficult for nonprofessionals. Our system automates the process and allows anyone to obtain his or her original knitting patterns from a 3D model. The system first covers the surface of the model with parallel winding strips of constant width. The system then samples the strip at constant intervals to convert it into a knitting pattern. The result is presented in a standard visual format so that the user can easily refer it during actual knitting. We show several examples of knitted animals created using the system.

Pillow: Interactive Flattening of a 3D Model for Plush Toy Design

Pillow is an interactive pattern-design system for creating plush toys. The user imports a 3D surface model into the system and specifies the segmentation boundaries interactively by drawing seam lines on the model surface. Based on this segmentation, the system generates a 2D pattern by flattening each outlined region, and then visualizes the shape of the resulting plush toy by applying a simple physics simulation. If the result is not satisfactory, the user can make different seam lines. This closed-loop framework allows users to experiment with various seam patterns before actually working on real fabric to obtain the best-looking result. The system also estimates total sewing time based on the total length of the seam lines. We implemented the system to produce plush toys and a balloon.

Knitty: 3D Modeling of Knitted Animals with a Production Assistant Interface

Knitty is an interactive design system for creating knitted animals. The user designs a 3D surface model using a sketching interface. The system automatically generates a knitting pattern and then visualizes the shape of the resulting 3D animal model by applying a simple physics simulation. The user can see the resulting shape before beginning the actual knitting. The system also provides a production assistant interface for novices. The user can easily understand how to knit each stitch and what to do in each step. In a workshop for novices, we observed that even children can design their own knitted animals using our system.

Interactive Cover Design Considering Physical Constraints

We developed an interactive system to design a customized cover for a given three‐dimensional (3D) object such as a camera, teapot, or car. The system first computes the convex hull of the input geometry. The user segments it into several cloth patches by drawing on the 3D surface. This paper provides two technical contributions. First, it introduces a specialized flattening algorithm for cover patches. It makes each two‐dimensional edge in the flattened pattern equal to or longer than the original 3D edge; a smaller patch would fail to cover the object, and a larger patch would result in extra wrinkles. Second, it introduces a mechanism to verify that the user‐specified opening would be large enough for the object to be removed. Starting with the initial configuration, the system virtually “pulls” the object out of the cover while avoiding excessive stretching of cloth patches. We used the system to design real covers and confirmed that it functions as intended.

Designing plush toys with a computer

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 users input stroke. We successfully demonstrated that nonprofessional users could design plush toys or balloon easily using Plushie.

Generating Graphical Reports on Cardiac Catheterization

Electronic medical recording systems [1-4] have become widespread due to the improve‐ ment in hardware performance and user interfaces. Some recent systems are designed to support doctor–patient communication using a tablet PC [5-6]. However, usability is still an issue and medical professionals need more such user-friendly interfaces. To make these sys‐ tems accessible to inexperienced users and to reduce the overhead of data entry, we have been developing various pen-based electronic medical recording systems [7-8]. Pen-based computing is an active research area for both user interfaces and computer graphics. Our work is based on recent advances in this area, especially the freeform user interfaces pro‐ posed by Igarashi [9]. Using this approach, the user draws freehand lines on the screen as‐ sisted by the system, and the result is directly stored as a vector image. Our systems feature special purpose functions for pen input including three-dimensional (3D) sketching, useridentification, and handwritten character recognition and search [8]. They are designed to help medical professionals to think more freely when working on difficult problems without being constrained by cumbersome interfaces.

Automatically adding seam allowance to cloth pattern

Various methods have been proposed for novice users to design their own garments using computers recently [Igarashi and Hughes 2002; Turouin et al. 2007]. These systems automatically generate a 2D cloth pattern from user input and the user can create a real garment by sewing the pattern together. To sew a real fabric, one also needs to leave an appropriate seam allowance when cutting the two-dimensional (2D) pattern. Difference seam allowances result in different look of the resulting garment [Hu et al. 1997], so appropriate design of seam allowance is very important. However, traditional computational pattern generation methods did not automatically generate seam allowances mainly because the target users were expert users and they prefer to manually add seam allowances. However, it is difficult for a novice user to add appropriate seam allowance manually and it is desirable that the system automatically create cloth pattern that takes seam allowance into account.