Tomoaki Moriya

Non-photorealistic rendering technique for depicting 3D objects motion

A still image extracted from a 3D animation sequence does not contain any information about the motions of 3D objects. In order to represent fast-moving 3D objects in a still image, the motion blur technique has been used. However, it cannot easily depict other kinds of motions. Several non-photorealistic rendering approaches [1] [2] have been proposed to depict the motions of 3D objects using “speed lines”. Speed lines, introduced by Masuch [1], are defined and drawn as difference vectors between the current and previous position vectors of the vertices of 3D object contours on a projected screen plane. Kawagishi et al. [2] generated very thin polygons instead of difference vectors. However, it is a tedious task to describe speed line types suitable for motion speed manually and repeatedly. We are studying a new non-photorealistic rendering technique that can depict various kinds of motions of 3D objects in animation scenes automatically and in real time. First, a motion is divided into a translation of and a rotation around the object’s center of gravity. For translation motion, we obtain the difference vectors of only the object’s center of gravity instead of those of the vertices of the 3D object’s contours. Texture-mapped polygons are generated as speed lines. Experimental results verify that our technique is effective and efficient enough to depict various motions of 3D objects automatically in real time.

Rust aging simulation considering object's geometries

Realistic representation of nature scenes is one of the most challenging areas in computer graphics community. There are important factors to synthesize realistic scenes in 3D CG which are decayed materials such as dead trees, weathered statues, rusty metals and so on. We are interested in the methodology for simulating its decaying processes. In this paper, we propose a simple method for rust aging simulation based on a probabilistic cellular automaton model taking into account objects geometries.

Real-time Manga -like depiction based on interpretation of bodily movements by using Kinect

In order to enrich visual communications, we propose a real-time system that interprets bodily movements by using Kinect [Kinect 2012]. Spatial and temporal positions of joints of body movements are captured by using Kinect. Based on captured data analysis, intensions of movements are interpreted. Finally, our system can automatically attach various Manga-like effects, such as speed lines, focus lines, or motion blur, to live action movies in real time. In addition, voice recognition function extends universality of our systems communication capabilities.

A stereoscopic representation of impossible rectangle twisted torus figure

Impossible figure is a figure which looks realizable at first glance, but is not actually realizable as perceived by the human eyes. Optical illusion object is a three dimensional object made to be an impossible figure when viewed from a specific viewpoint. The viewpoint that realizes an optical illusion is called as an illusion viewpoint. An optical illusion object is not perceived as an impossible figure when a viewpoint moves away from an illusion viewpoint.

An Extended Non-Photorealistic Rendering Technique for Depicting Motions of Multiple 3D Objects

In order to enrich visual communications, we present a non-photorealistic rendering technique that depicts motion of 3D objects in a still image. To realize this technique, ¿speed line¿, one of the most familiar techniques in Japanese cartoon ¿manga¿, is introduced. Our technique firstly decomposes a combined motion of 3D objects into a translational motion of the center of gravity of the object and its rotational motion. Then, to depict motion of the 3D object, we render texture-mapped polygons that generated from a series of geometrical positions of the 3D object that represent its animation progress with the 3D objects. Textures mapped to the polygons are changed automatically according to the speed of the 3D object. Experimental results verify that our technique is effective enough to automatically depict various motions of 3D objects in real time.

Creativity enhancement of painterly rendering using a suggestive interface

Abstract Non-photorealistic rendering (NPR) can use various parameters and techniques to automatically generate a wide range of images with different painterly appearances. However, a real painting is the result of a creative process, and traditionally, many artists have developed their own media, styles, and techniques. Fortunately, the computer can also be used in different ways, for instance, as a tool to support and enhance creativity. We propose a system to interactively generate a painterly image through a suggestive interface. After the artist intuitively selects a region, our system immediately offers different suggestions of NPR modifications. The multidimensional NPR parameter space is transformed in a more perceptual space by optimization, which is validated by a user study. The suggested images generated from sampled parametric variations are displayed according to our perceptual distance. Through the same interface, our system allows for refinement or exploration without any need to understand the various parameters involved in generating NPR effects. The interest of our suggestive interface is supported by another user study, where participants felt that it stimulated their creativity as they interactively and iteratively created painterly images by choosing suggested images for the selected regions. Another experiment showed that different viewers found the resulting images more creative than their initial automatically generated images.

An icicle generation model based on the SPH method

classroom use is granted without fee provided that copies are not made or distributed for commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for third-party components of this work must be honored. For all other uses, contact the Owner/Author. SIGGRAPH 2014, August 10 – 14, 2014, Vancouver, British Columbia, Canada. 2014 Copyright held by the Owner/Author. ACM 978-1-4503-2958-3/14/08 An icicle generation model based on the SPH method Masaki Sato Jun Kobayashi Tomoaki Moriya Yuki Morimoto Tokiichiro Takahashi Tokyo Denki University UEI Research Adachi-Ku, Tokyo, Japan {m-sato, j-kobayashi, moriya, yuki, toki}@vcl.jp

Animating impossible figure from twisted torus to penrose stairs

When a start prism and an end prisms vertices are in the same values on the projection screen, the shape model is viewed as an impossible figure. Therefore, if we can create the optical illusion object according to an arbitrary viewpoint, it is possible to create impossible figure that is viewed from the arbitrary viewpoint. We have already proposed and developed a method which animates impossible rectangle twisted torus figure from any viewpoint interactively and in real time[Nakatsu, et al. 2012]. Although the method of creating an optical illusion based on the optical illusion objects is a simple and classic method, this is powerful and robust all the more. Even when a viewpoint is moved to a wide range of area, the animation of an impossible figure can be created. We have extended the application of this principle to Penrose Stairs, and this paper presents that it was successfully realized when the viewpoint was moved freely.

Conducting and performing virtual orchestra

There are a lot of people who have had yearning for conducting orchestra. It must be a very pleasant experience to coordinate orchestra performance with your own conduct, but it requires a vast amount of money. With such needs, there have been researches to simulate the situation of conducting orchestra by using gesture recognition [Usa][Baba][Sunagawa]. But, they do not generate performance scenes.

A walking motion morphing method based on statistical data of the elderly

Technologies to create numerous motions from a motion data are sought for in order to increase a variety of motions of 3D characters in virtual space. A number of methods have been proposed to increase the variation of walking of people. They consider physical geometric attributes such as standing height and seating height, and motion attributes, but do not consider the postural changes with aging.