vriphys12

Permanent URI for this collection

https://diglib.eg.org/handle/10.2312/1025

Browse

Browsing vriphys12 by Subject "Computational Geometry and Object Modeling"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Bézier Shell Finite Element for Interactive Surgical Simulation
    (The Eurographics Association, 2012) Golembiovský, Tomá¹; Duriez, Christian; Jan Bender and Arjan Kuijper and Dieter W. Fellner and Eric Guerin
    There is a strong need, in surgical simulations, for physically based deformable model of thin or hollow structures. The use of shell theory allows to have a well-founded formulation resulting from continuum mechanics of thin objects. However, this formulation asks for second order spatial derivatives so requires the use of complex elements. In this paper, we present a new way of building the interpolation: First, we use the trianular cubic Bézier shell to allow for a good continuity inside and between the elements and second, we build a kinematic mapping to reduce the degrees of freedom of the element from 10 control points with 3 Degrees of Freedom (
  • Thumbnail Image
    Item
    Fast Simulation of Inextensible Hair and Fur
    (The Eurographics Association, 2012) Müller, Matthias; Kim, Tae-Yong; Chentanez, Nuttapong; Jan Bender and Arjan Kuijper and Dieter W. Fellner and Eric Guerin
    In this short paper we focus on the fast simulation of hair and fur on animated characters. While it is common in films to simulate single hair strands on virtual humans and on furry animals, those features are either not present on characters in computer games or modeled with simplified textured meshes. The main difficulty of simulating hair in real time applications is the sheer number of hair strands and the fact that each hair is inextensible. Keeping thousands of deformable objects from being stretched is computationally expensive. In this paper, we present a robust method for simulating hair and fur that guarantees inextensiblity with a single iteration per frame. For an iteration count this low, existing methods either become unstable or introduce a substantial amount of stretching. Our method is geometric in nature and able to simulate thousands of inextensible hair strands in real time.
  • Thumbnail Image
    Item
    An Implicit Tensor-Mass Solver on the GPU for Soft Bodies Simulation
    (The Eurographics Association, 2012) Faure, Xavier; Zara, Florence; Jaillet, Fabrice; Moreau, Jean-Michel
    The realistic and interactive simulation of deformable objects has become a challenge in Computer Graphics. In this paper, we propose a GPU implementation of the resolution of the mechanical equations, using a semi-implicit as well as an implicit integration scheme. At the contrary of the classical FEM approach, forces are directly computed at each node of the discretized objects, using the evaluation of the strain energy density of the elements. This approach allows to mix several mechanical behaviors in the same object. Results show a notable speedup of 30, especially in the case of complex scenes. Running times shows that this efficient implementation may contribute to make this model more popular for soft bodies simulations.
  • Thumbnail Image
    Item
    Physics-based Augmented Reality for 3D Deformable Object
    (The Eurographics Association, 2012) Haouchine, Nazim; Dequidt, Jérémie; Kerrien, Erwan; Berger, Marie-Odile; Cotin, Stéphane; Jan Bender and Arjan Kuijper and Dieter W. Fellner and Eric Guerin
    This paper introduces an original method to perform augmented or mixed reality on deformable objects. Compared to state-of-the-art techniques, our method is able to track deformations of volumetric objects and not only surfacic objects. A flexible framework that relies on the combination of a 3D motion estimation and a physicsbased deformable model used as a regularization and interpolation step allows to perform a non-rigid and robust registration. Results are exposed, based on computer-generated datasets and video sequences of real environments in order to assess the relevance of our approach.
  • Thumbnail Image
    Item
    Real-time Hair Simulation with Efficient Hair Style Preservation
    (The Eurographics Association, 2012) Han, Dongsoo; Harada, Takahiro; Jan Bender and Arjan Kuijper and Dieter W. Fellner and Eric Guerin
    Hair can be a prominent feature of characters in real-time games. In this paper, we propose hair simulation with efficient preservation of various hair styles. Bending and twisting effects are crucial to simulate curly or wavy hair. We propose local and global shape constraints and parallel methods to update local and global transforms to find goal positions. All three methods show good visual quality and take only a small fraction of rendering time. This simulation runs on the GPU and works smoothly as a part of rendering pipeline. Simulating around 20,000 strands composed of total 0.22 million vertices takes less than 1 millisecond. Simulation parameters such as stiffness or number of iterations for shape constraints can be manipulated by users interactively. It helps designers choose the right parameters for various hair styles and conditions. Also the simulation can handle various situations interactively.
  • Thumbnail Image
    Item
    Synthesizing Balancing Character Motions
    (The Eurographics Association, 2012) Kenwright, Ben; Jan Bender and Arjan Kuijper and Dieter W. Fellner and Eric Guerin
    This paper presents a novel method for generating balancing character poses by means of a weighted inverse kinematic constraint algorithm. The weighted constraints enable us to control the order of priority so that more important conditions such as balancing can take priority over less important ones. Maintaining a balancing pose enables us to create a variety of physically accurate motions (e.g., stepping, crouching). Balancing is achieved by controlling the location of the overall centre of mass of an articulated character; while the secondary constraints generate poses from end-effectors and trajectory information to provide continuous character movement. The poses are created by taking into account physical properties of the articulated character, that include joint mass, size, strength and angular limits. We demonstrate the successfulness of our method by generating balancing postures that are used to produce controllable character motions with physically accurate properties; likewise, our method is computationally fast, flexible and straightforward to implement.