3D Weather – Towards a Real-time 3D Simulation of Localised Weather presented at EVA 2011

Weather forecasts are nearly always portrayed from either a satellite view perspective, a numerical or symbol based representation. None of these methods actually portray weather visually from the point of view of the observer, that is, they do not represent our experience of weather. This problem presents a challenge to displaying weather using real-time 3D computer graphics. 3D Weather is a proposed method to solve this problem, to create more believable representations of the weather using real weather data. By employing computer graphic techniques and computer game concepts the project intends to create a localized display of weather using mapping and weather data. Started in 2010, the project has been exploring existing techniques, scoping out the needs of stakeholders (such as the Met Office), and creating a prototype to explore the issues. The paper concludes that the quest for realism with computer graphics can be a double-edged sword. It can lead to expectations of accuracy in the data its meant to represent, which can be desired, but in the case of the weather forecast the representation is not necessary what the weather will be, its what the weather might be. The continuing project will explore the balance of issues when representing the weather for past events as well as for forecasts

Procedural 3D Caves, Clouds and Architecture Generation Method Based on Shape Grammar and Morphing

This paper presents a new procedural 3D modelconstructionalgorithm that benefits from a combination ofdiscrete and continuous modeling approaches. Our algorithmmodels complex scene components such as caves, architecturalbuildings, and clouds. The method combines the discretedescriptiveness of shape grammars with the continuous flexibilityof shape morphing. This combination allows for a modelingapproach that can be controlled by a morphing parameter toproduce various types of geometry. In the paper, we focus on thedescription of the algorithm while also showing its capabilities ingenerating complex scene components

Real Time Rendering of Atmospheric Scattering and Volumetric Shadows

International audienceReal time rendering of atmospheric light scattering is one of the most difficult lighting effect to achieve in computer graphics. This paper presents a new real time method which renders these effects including volumetric shadows, which provides a great performance improvement over previous methods. Using an analytical expression of the light transport equation we are able to render directly the contribution of the participating medium on any surface. The rendering of shadow planes, sorted with a spatial coherence technique, and in the same philosophy than the shadow volume algorithm will add the volumetric shadows. Realistic images can be produced in real time for usual graphic scenes and at a high level framerate for complex scenes, allowing animation of lights, objects or even participating media. The method proposed in this paper use neither precomputation depending on light positions, nor texture memory

Rendering Clouds in Real Time

Práce se zabývá algoritmy schopnými zobrazit mraky v reálném čase. Teoretická část popisuje fyzikální princip oblaků a seznamuje s vybranými metodami pro jejich modelování a vykreslování. Cílem praktické části je implementovat jeden z algoritmů, schopný běžet v reálném čase a vyvinout aplikaci, která jej bude demonstrovat.This thesis is about algorithms which render clouds in real time. The theoretical section deals with clouds in real world and also describes some algorithms for modeling and rendering them. The aim of practical section is implement one of these real time algorithms and develop demonstrational application.

A Review on Light Shafts Rendering for Indoor Scenes

Rendering light shafts is one of the important topics in computer gaming and interactive applications. The methods and models that are used to generate light shafts play crucial role to make a scene more realistic in computer graphics. This article discusses the image-based shadows and geometric-based shadows that contribute in generating volumetric shadows and light shafts, depending on ray tracing, radiosity, and ray marching technique. The main aim of this study is to provide researchers with background on a progress of light scattering methods so as to make it available for them to determine the technique best suited to their goals. It is also hoped that our classification helps researchers find solutions to the shortcomings of each method

Real-time rendering of physically-based cloud simulations for university undergraduate research fellows

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 38-39).Computers today employ simulations of physical phenomena such as wind and fire and other physical properties in many common applications, including programs meant for training and entertainment. We focus particularly on the realistic simulation of cloud formation and existence on current commercially-available computers. One of the challenges associated with this simulation is its display onto a computer screen, often referred to as rendering. We will present a brief overview of existing cloud rendering techniques and compare their effectiveness to rendering a simulation as it occurs. We will then suggest our rendering method which relies upon the use of three-dimensional textures and modified Gaussian transfer functions for the self-shadowing properties associated with clouds. We will analyze these results, focusing on frame rates and visual appearance, and then conclude by suggesting further work on this topic

Real-time smoke rendering using compensated ray marching

We present a real-time algorithm called compensated ray march-ing for rendering of smoke under dynamic low-frequency environ-ment lighting. Our approach is based on a decomposition of the input smoke animation, represented as a sequence of volumetric density fields, into a set of radial basis functions (RBFs) and a se-quence of residual fields. To expedite rendering, the source radi-ance distribution within the smoke is computed from only the low-frequency RBF approximation of the density fields, since the high-frequency residuals have little impact on global illumination under low-frequency environment lighting. Furthermore, in computing source radiances the contributions from single and multiple scatter-ing are evaluated at only the RBF centers and then approximated at other points in the volume using an RBF-based interpolation. A slice-based integration of these source radiances along each view ray is then performed to render the final image. The high-frequency residual fields, which are a critical component in the local appear-ance of smoke, are compensated back into the radiance integral dur-ing this ray march to generate images of high detail. The runtime algorithm, which includes both light transfer simula-tion and ray marching, can be easily implemented on the GPU, and thus allows for real-time manipulation of viewpoint and lighting, as well as interactive editing of smoke attributes such as extinction cross section, scattering albedo, and phase function. Only moderate preprocessing time and storage is needed. This approach provides the first method for real-time smoke rendering that includes sin-gle and multiple scattering while generating results comparable in quality to offline algorithms like ray tracing

Procedural Cloudscapes

International audienceWe present a phenomenological approach for modeling and animating cloudscapes. We propose a compact procedural model for representing the different types of cloud over a range of altitudes. We define primitive-based field functions that allow the user to control and author the cloud cover over large distances easily. Our approach allows us to animate cloudscapes by morphing: instead of simulating the evolution of clouds using a physically-based simulation, we compute the movement of clouds using key-frame interpolation and tackle the morphing problem as an Optimal Transport problem. The trajectories of the cloud cover primitives are generated by solving an Anisotropic Shortest Path problem with a cost function that takes into account the elevation of the terrain and the parameters of the wind field