Real-time Physics Based Simulation for 3D Computer Graphics

Restoration of realistic animation is a critical part in the area of computer graphics. The goal of this sort of simulation is to imitate the behavior of the transformation in real life to the greatest extent. Physics-based simulation provides a solid background and proficient theories that can be applied in the simulation. In this dissertation, I will present real-time simulations which are physics-based in the area of terrain deformation and ship oscillations. When ground vehicles navigate on soft terrains such as sand, snow and mud, they often leave distinctive tracks. The realistic simulation of such vehicle-terrain interaction is important for ground based visual simulations and many video games. However, the existing research in terrain deformation has not addressed this issue effectively. In this dissertation, I present a new terrain deformation algorithm for simulating vehicle-terrain interaction in real time. The algorithm is based on the classic terramechanics theories, and calculates terrain deformation according to the vehicle load, velocity, tire size, and soil concentration. As a result, this algorithm can simulate different vehicle tracks on different types of terrains with different vehicle properties. I demonstrate my algorithm by vehicle tracks on soft terrain. In the field of ship oscillation simulation, I propose a new method for simulating ship motions in waves. Although there have been plenty of previous work on physics based fluid-solid simulation, most of these methods are not suitable for real-time applications. In particular, few methods are designed specifically for simulating ship motion in waves. My method is based on physics theories of ship motion, but with necessary simplifications to ensure real-time performance. My results show that this method is well suited to simulate sophisticated ship motions in real time applications

Contact Dynamics Simulation for Space Robotics Applications

Abstract—The subject of this paper are contact dynamics simulation methods for two different examples of space robotics applications: Satellite docking in GEO and rover locomotion on planetary surfaces. The according modeling techniques include contact dynamics computation a) between two polygonal surfaces according to the elastic foundation model theory and b) between digital elevation grid surfaces and point cloud surfaces with application of Bekker’s empirical terramechanics functions. The presented simulation results, which are taken from two ongoing projects, SMART-OLEV with satellite docking simulations and ExoMars with rover drawbar pull simulations, demonstrate that contact dynamics simulations can provide helpful inputs in terms of mission feasibility assessment and system design. I

Drift-diffusion based real-time dynamic terrain deformation

In the natural world, terrains are dynamic entities that change their morphology due to their interaction with other agents in the environment. However, in real-time applications terrains are often represented as static meshes, which present no interaction capabilities. This paper presents a novel real-time 2D method for dynamic terrain simulations, aimed for applications in the entertainment industry. This method is based on a Dynamically-Displaced Height-map and on the numerical solutions, obtained using an Euler method, of a modified drift-diffusion equation. The method allows objects to interact with the terrain and to deform it in real time, it is easy to implement and generates different kinds of realistic tracks depending on the soil composition

Creating deformations and tunnels in a surface using layered geometry with adaptive filtering

With this thesis, I present a method for creating footprints and tunnels in a surface through the use of layered geometry. Rather than using a single geometric surface, deformations are created through the interaction of a polygonal object with multiple layered planes. Contrary to common methods such as solely using displacement maps or techniques used in fluid dynamics, none of the layered geometry moves. With adaptive filtering and layered geometry, one can create complex deformations resulting from sliding, digging, and surfacing. Its volumetric nature allows interaction to create overlapping shapes, tunnels, and holes in a surface, while alleviating the ultimate problem of broken geometry

Terrain Navigation Skills and Reasoning

We describe a real-time model of terrain traversal by simulated human agents. Agent navigation includes a variety of simulated sensors, terrain reasoning with behavioral constraints, and detailed simulation of a variety of locomotion techniques. Our Kinematic Locomotion Generation Module (KLOG) generates various terrain navigation skills as well as both rhythmic and non-rhythmic variations of these skills. The terrain navigation skills include curved path walking, lateral or backward stepping, running, and the transitions between walking and running for motion continuity. Locomotion attributes such as pelvis rotation and translation and torso flexion and twist are used to modify the KLOG skills so that realistic looking rhythmic locomotion or non-rhythmic variations, such as ducking under a low hanging branch of a tree, can be achieved. The path through the terrain is incrementally computed by a behavioral reasoning system configuring a behavioral feedback network. A number of sensors acquire information on object range, passageways, obstacles, terrain type, exposure to hostile agents and so on. The behavioral reasoner weighs this information along with collision avoidance, cost, danger minimization, locomotion types and other behaviors available to the agent and incrementally attempts to reach a goal location. Since the system is reactive, it can respond to moving obstacles, changing terrain, or unexpected events due to hostile agents or the effects of limited perception

The Country West of the Mississippi River

William Hoynes delivered this lecture on The Country West of the Mississippi River on April 18, 1885. The Notre Dame Scholastic reprinted the lecture in three issues: April 25, 1885; May 9, 1885; and May 16, 1885

The Country West of the Mississippi River

William Hoynes delivered this lecture on The Country West of the Mississippi River on April 18, 1885. The Notre Dame Scholastic reprinted the lecture in three issues: April 25, 1885; May 9, 1885; and May 16, 1885

Simulating large volumes of granular matter

Master of ScienceDepartment of Computer ScienceDaniel AndresenModern techniques for simulating granular matter can produce excellent quality simulations, but usually involve a great enough performance cost to render them ineffective for real time applications. This leaves something to be desired for low-cost systems and interactive simulations which are more forgiving to inaccurate simulations, but much more strict in regards to the performance of the simulation itself. What follows is a proposal for a method of simulating granular matter that could potentially support millions of particles and several types for each particle while maintaining acceptable frame rates on consumer level hardware. By leveraging the power of consumer level graphics cards, effective data representation, and a model built around Cellular Automata a simulation can be run in real time

A multi-scale model for coupling strands with shear-dependent liquid

We propose a framework for simulating the complex dynamics of strands interacting with compressible, shear-dependent liquids, such as oil paint, mud, cream, melted chocolate, and pasta sauce. Our framework contains three main components: the strands modeled as discrete rods, the bulk liquid represented as a continuum (material point method), and a reduced-dimensional flow of liquid on the surface of the strands with detailed elastoviscoplastic behavior. These three components are tightly coupled together. To enable discrete strands interacting with continuum-based liquid, we develop models that account for the volume change of the liquid as it passes through strands and the momentum exchange between the strands and the liquid. We also develop an extended constraint-based collision handling method that supports cohesion between strands. Furthermore, we present a principled method to preserve the total momentum of a strand and its surface flow, as well as an analytic plastic flow approach for Herschel-Bulkley fluid that enables stable semi-implicit integration at larger time steps. We explore a series of challenging scenarios, involving splashing, shaking, and agitating the liquid which causes the strands to stick together and become entangled.This work was supported in part by the National Science Foundation under Grant Nos.: 1717178, 1319483, CAREER-1453101, the Natu- ral Sciences and Engineering Research Council of Canada under Grant No. RGPIN-04360-2014, SoftBank Group, Pixar, Adobe, and SideFX

Annual reports of town officers and committees for the town of Springfield, New Hampshire, including vital statistics, for the year 2019.

This is an annual report containing vital statistics for a town/city in the state of New Hampshire