Abstract This paper proposes a novel method that enhances the optimization‐based elastic body solver. The proposed method tackles the element inversion problem, which is prevalent in the prediction‐projection approach for numerical simulation of elastic bodies. At the prediction stage, our method alleviates inversions such that the subsequent projection solver can benefit in stability and efficiency. To prevent excessive suppression of predicted inertial motion when alleviating, we introduce a velocity decomposition method and adapt only the non‐rigid motion while preserving the rigid motion, that is, linear and angular momenta. Thanks to the respected inertial motion in the prediction stage, our method produces lively motions while keeping the entire simulation more stable. The experiments demonstrate that our alleviation method successfully stabilizes the simulation and improves the efficiency particularly when large deformations hamper the solver.

Abstract This paper presents a novel method that automatically reconstructs pipes in real time using an RGB‐D camera. The input image is decomposed into superpixels, and a pipe element, which is a 3D circle lying on the pipe surface, is generated for each superpixel. Over frames, the pipe elements are grouped into sequences and are finally modeled in parametric equations. The method is tested in daily settings, where the pipes may be curved and their radii may vary along the axes. The test results show that the method is able to reconstruct pipes efficiently, precisely and robustly.

Abstract In general, it is not easy to simulate an elastic body that undergoes large deformations. Especially when its elements are inverted or tangled, that is, when its vertices penetrate its polygons, simulation often fails. In this paper, we propose a simple yet highly effective method for alleviating the inversion problems of elastic bodies. Our experiments made with typical optimization‐based solvers demonstrate that the proposed method successfully stabilizes the solvers and produces visually plausible motions. We believe that our method can be widely adopted by a variety of state‐of‐the‐art elastic‐body simulators thanks to its simplicity.

This paper presents a novel method for simulating inducible rigid magnets efficiently and stably. In the proposed method, inducible magnets are magnetized by a modified magnetization dynamics, so that the magnetic equilibrium can be obtained in a computationally efficient manner. Furthermore, our model of magnetic forces takes magnetization change into account to produce stable motions of inducible magnets. The experiments show that the proposed method enables a large-scale simulation involving a huge number of inducible magnets.

This paper presents a mobile AR system for visualizing airflow and temperature change made by virtual air conditioners. Even though there have been efforts to integrate the results of airflow/temperature simulation into the real world via AR, they support neither interactive modeling of the environments nor real-time simulation. This paper presents an AR system, where 3D mapping and air conditioner installation are made interactively, and then airflow/temperature simulation and visualization are made at real time. The proposed system is designed in a client-server architecture, where the server is in charge of simulation and the rest is taken by the client.

A non-Euclidean space is characterized as a manifold with a specific structure that violates Euclid's postulates. This paper proposes to approximate a manifold with polytopes. Based on the scene designer's specification, the polytopes are automatically concatenated and embedded in a higher-dimensional Euclidean space. Then, the scene is navigated and rendered via novel methods tailored to concatenated polytopes. The proof-of-concept implementation and experiments with it show that the proposed methods bring the virtual-world users unusual and fascinating experiences, which cannot be provided in Euclidean-space applications.

Recent advances in 3D reconstruction and tracking technologies have made it possible to volumetrically capture human body and performance at real time. In the field of human-computer interaction, however, no works have been reported on the user study made with such volumetric capture avatars. This paper investigates how the volumetric capture avatar affects users' sense of social presence in immersive virtual environments. In our experiments, the volumetric capture avatar of an actor is compared with the actor captured in 2D video and another 3D avatar obtained by pre-scanning the actor. The experiment results show that users have the highest sense of social presence with the volumetric capture avatar when performing dynamic tasks whereas they have higher sense of social presence with the volumetric capture avatar and 2D video than with the pre-scanned avatar when performing static tasks. These imply that the emerging volumetric capture techniques can be an attractive tool for mixed reality, telepresence, and many other 3D applications.

Abstract We propose a novel method for simulating rigid magnets in a stable way. It is based on analytic solutions of the magnetic vector potential and flux density, which make the magnetic forces and torques calculated using them seldom diverge. Therefore, our magnet simulations remain stable even though magnets are in close proximity or penetrate each other. Thanks to the stability, our method can simulate magnets of any shapes. Another strength of our method is that the time complexities for computing the magnetic forces and torques are significantly reduced, compared to the previous methods. Our method is easily integrated with classic rigid‐body simulators. The experiment results presented in this paper prove the stability and efficiency of our method.

The goal of this paper is to simulate the interactions between magnetic objects in a physically correct way. The simulation scheme is based on magnetization dynamics, which describes the temporal change of magnetic moments. For magnetization dynamics, the Landau-Lifshitz-Gilbert equation is adopted, which is widely used in micromagnetics. Through effectively-designed novel models of magnets, it is extended into the macro scale so as to be combined with real-time rigid-body dynamics. The overall simulation is stable and enables us to implement mutual induction and remanence that have not been tackled by the state-of-the-art technique in magnet simulation. The proposed method can be applied to various fields including magnet experiments in the virtual world.