Kaisei Sakurai

Modelling of Non-Periodic Aggregates Having a Pile Structure

This paper presents a procedure for modelling aggregates such as piles that consist of arbitrary components. The method generates an aggregate of components that need to be accumulated, and an aggregate shape represents the surface of the target aggregate. The number of components and their positions and orientations are controlled by five parameters. The components, the aggregate shape and the parameters are the inputs for the method which involves placement and refinement steps. In the placement step, the orientation and initial position of a component are determined by a non‐periodic placement such that each component overlaps its neighbours. In the refinement step, to construct a pile structure, the position of each component is adjusted by reducing the overlap.

Procedural modeling of multiple rocks piled on flat ground

There are many rocks in the natural world, and shape modeling for rocks is important to represent the ground. Procedural modeling is an effective methods for this purpose.

Procedural modeling of leather texture with structural elements

This paper proposes a simple generation method for realistic leather texture. Leather surface consists of five structural elements, which are cristae, sulci, wrinkles, pockets and pores, which characterize the visual impression of the leather texture.We classified structural elements by observing real leather surface. To represent the elements, the method extracts features of real textures in order to generate an outline of each element. Then the method computes each element is three-dimensional shapes by a function which defines a continuous surface. Our method generates detailed leather texture, and is easy to handle, with simple procedures and intuitive parameters.

Baked crepe texture generation

We have built a simple model for crepe texture without fluid simulation.

Fabricating Reflectors for Displaying Multiple Images

A great deal of attention has been devoted to the fabrication of reflectors that can display different color images when viewed from different directions not only in industry but also for the arts. Although such reflectors have previously been successfully fabricated, the number of images displayed has been limited to two or they suffer from ghosting artifacts where mixed images appear. Furthermore, the previous methods need special hardware and/or materials to fabricate the reflectors. Thus, those techniques are not suitable for printing reflectors on everyday personal objects made of different materials, such as name cards, letter sheets, envelopes, and plastic cases. To overcome these limitations, we propose a method for fabricating reflectors using a standard ultraviolet printer (UV printer). UV printer can render a specified 2D color pattern on an arbitrary material and by overprinting the printed pattern can be raised, that is, the printed pattern becomes a microstructure having color and height. We propose using these micro structures to formulate a method for designing spatially varying reflections that can display different target images when viewed from different directions. The microstructure is calculated by minimizing an objective function that measures the differences between the intensities of the light reflected from the reflector and that of the target image. We show several fabricated reflectors to demonstrate the usefulness of the proposed method.

Psychophysical experiment exploring appearance element for realistic clothes

Graphic editing programs such as Adobe Photoshop can change the appearances of object surfaces in a scene while maintaining reality; however, the reasons are not well understood. We aim to reveal an appearance element that maintains reality and reflects the element in computer graphics (CG) applications such as augmented reality. This report focuses on realistic clothes surfaces because clothes are frequently used in applications. To understand what contributes to a realistic appearance, we explored perceptions from still images and movies in two psychophysical experiments. Experiment #1 explored the most contributing element for perceptions when observing clothes. Experiment #2 confirmed that the same element also contribute to movies with an interactive system.

A procedural modeling of woven textiles with fuzz

The purpose of this article is to propose a procedure for generating woven textiles with fuzz through the modeling of surface staples. The procedure guarantees to control the appearance of fuzz. In woven textiles, fuzz is the result of staples untwisted from the yarns, as shown in Fig. 1(a). Staple is of average length in natural fiber (e.g. wool and cotton), but in silk or chemical fiber its length is shorter. Our modeling procedure also takes into account the arbitrary woven design which creates a quadrilateral mesh formed by warps and wefts, with the exception of gauze and leno weaves (twisting adjacent warps), as shown in Fig. 1 (b) and (c). The procedure improves the representation of woven textile.

Leather texture generation considering sulci flow

This paper introduces a new method for generating leather texture by means of cell simulation considering sulci flow. The cell simulation is based on an analogy of cracks on drying or aging surface. The method uses a mass-spring model for generating sulci flow on a surface of leather. A user can specify a sulcus shape by applying a radial basis function (RBF) for its profile.