Bezier Clippingおよびその計算機支援形状設計への応用

Recently, computer aided geometry design for industrial products has become popular. Geometry design including free form surface is very significant in CAD/CAM system. In geometry designs there are some problems that need to be solved such as curve-curve intersection, surface-surf ace intersection, and curve-surf ace intersection. A display method of desired shapes is also very important. To display curved surfaces we have to solve a hidden line problem and a hidden surface problem. Shading models including shadowing, reflection, and refraction are required to get photo-realistic images of designed shapes. This paper proposes Bezier clipping method which can solve all of the problems mentioned above. Bezier clipping is a robust iterative method which can solve functions expressed by polynomials of a high degree. This paper describes the basic idea of Bezier clipping and its application to computer aided geometry design and computer graphics

A Survey of Ocean Simulation and Rendering Techniques in Computer Graphics

This paper presents a survey of ocean simulation and rendering methods in computer graphics. To model and animate the ocean's surface, these methods mainly rely on two main approaches: on the one hand, those which approximate ocean dynamics with parametric, spectral or hybrid models and use empirical laws from oceanographic research. We will see that this type of methods essentially allows the simulation of ocean scenes in the deep water domain, without breaking waves. On the other hand, physically-based methods use Navier-Stokes Equations (NSE) to represent breaking waves and more generally ocean surface near the shore. We also describe ocean rendering methods in computer graphics, with a special interest in the simulation of phenomena such as foam and spray, and light's interaction with the ocean surface

Fast Simulation of Skin Sliding

Skin sliding is the phenomenon of the skin moving over underlying layers of fat, muscle and bone. Due to the complex interconnections between these separate layers and their differing elasticity properties, it is difficult to model and expensive to compute. We present a novel method to simulate this phenomenon at real--time by remeshing the surface based on a parameter space resampling. In order to evaluate the surface parametrization, we borrow a technique from structural engineering known as the force density method which solves for an energy minimizing form with a sparse linear system. Our method creates a realistic approximation of skin sliding in real--time, reducing texture distortions in the region of the deformation. In addition it is flexible, simple to use, and can be incorporated into any animation pipeline

Scoping Study for a Realistic Driving Simulator: Final Report.

1. INTRODUCTION This report documents the results of a study carried out between December 1989 and March 1990 to determine the most suitable equipment to be purchased for building a driving simulator at the Institute for Transport Studies at the University of Leeds. This "scoping study" was intended to accomplish three main tasks: 1. A review of existing facilities both in the UK and elsewhere in Europe to ascertain what has already been achieved and what is the current state of the art. 2. Initial discussions with potential users on desired features to be built in to the simulator. 3. Discussions with equipment suppliers in the light of what was found out in Tasks 1 and 2, so that the appropriate equipment could be specified. The report documents in subsequent sections the findings of the first two tasks. It then summarizes the conclusions that were reached on the overall simulator design, on the required features of the simulator and on the effort required to develop an operational simulator from the various hardware components. Finally, recommendations are made on the equipment to be purchased in the light of the recommended configuration, the discussion with equipment suppliers under Task 3 and the budget allocated

TVL₁ Planarity Regularization for 3D Shape Approximation

The modern emergence of automation in many industries has given impetus to extensive research into mobile robotics. Novel perception technologies now enable cars to drive autonomously, tractors to till a field automatically and underwater robots to construct pipelines. An essential requirement to facilitate both perception and autonomous navigation is the analysis of the 3D environment using sensors like laser scanners or stereo cameras. 3D sensors generate a very large number of 3D data points when sampling object shapes within an environment, but crucially do not provide any intrinsic information about the environment which the robots operate within. This work focuses on the fundamental task of 3D shape reconstruction and modelling from 3D point clouds. The novelty lies in the representation of surfaces by algebraic functions having limited support, which enables the extraction of smooth consistent implicit shapes from noisy samples with a heterogeneous density. The minimization of total variation of second differential degree makes it possible to enforce planar surfaces which often occur in man-made environments. Applying the new technique means that less accurate, low-cost 3D sensors can be employed without sacrificing the 3D shape reconstruction accuracy