Volume rendering of smoke propagation CFD data

ACM Transactions on Graphics, 2008

We present a real-time algorithm called compensated ray marching for rendering of smoke under dynamic low-frequency environment 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 sequence of residual fields. To expedite rendering, the source radiance distribution within the smoke is computed from only the lowfrequency RBF approximation of the density fields, since the highfrequency residuals have little impact on global illumination under low-frequency environment lighting. Furthermore, in computing source radiances the contributions from single and multiple scattering 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 appearance of smoke, are compensated back into the radiance integral during this ray march to generate images of high detail. The runtime algorithm, which includes both light transfer simulation 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 single and multiple scattering while generating results comparable in quality to offline algorithms like ray tracing.

Proceedings of the 28th annual conference on Computer graphics and interactive techniques - SIGGRAPH '01, 2001

In this paper, we propose a new approach to numerical smoke simulation for computer graphics applications. The method proposed here exploits physics unique to smoke in order to design a numerical method that is both fast and efficient on the relatively coarse grids traditionally used in computer graphics applications (as compared to the much finer grids used in the computational fluid dynamics literature). We use the inviscid Euler equations in our model, since they are usually more appropriate for gas modeling and less computationally intensive than the viscous Navier-Stokes equations used by others. In addition, we introduce a physically consistent vorticity confinement term to model the small scale rolling features characteristic of smoke that are absent on most coarse grid simulations. Our model also correctly handles the interaction of smoke with moving objects.

The Visual Computer, 2007

In this paper, we present a new fire animation and visualization scheme. The most difficult problem in creating fire animation is how to simulate the mechanism of emitting the light and heat of fire. We attack the difficulty by presenting a simulation scheme for the combustion process in voxelized space where the numerical solution of the classical fluid equations is implemented. Therefore, the combustion process is simulated at each voxel and the amount of heat generated at the voxel is estimated. The generated heat will increase the temperature at the voxel, which results in the increase of the turbulent motion of fire. We also propose a visualization scheme that is based on a photon mapping algorithm in order to render fire and various lighting effects of fire to the environments.

Proceedings of the 22nd annual conference on Computer graphics and interactive techniques - SIGGRAPH '95, 1995

Developing a visually convincing model of fire, smoke, and other gaseous phenomena is among the most difficult and attractive problems in computer graphics. We have created new methods of animating a wide range of gaseous phenomena, including the particularly subtle problem of modelling "wispy" smoke and steam, using far fewer primitives than before. One significant innovation is the reformulation and solution of the advection-diffusion equation for densities composed of "warped blobs". These blobs more accurately model the distortions that gases undergo when advected by wind fields. We also introduce a simple model for the flame of a fire and its spread. Lastly, we present an efficient formulation and implementation of global illumination in the presence of gases and fire. Our models are specifically designed to permit a significant degree of user control over the evolution of gaseous phenomena.

2000

This paper addresses the application of fire and smoke simulation and computational fluid dynamics tools to events taking place in the new engineering building on the campus of the University of Montreal. The development steps include 3D CAD modeling of the entire building, geometry transfer and airflow, and fire simulation with enhanced rendering considering the optical properties of smoke and

This paper presents an effort at developing a robust, interactive framework for rendering 3D fire in real-time in a production environment. Many techniques of rendering fire in non real-time exist and are constantly employed by the movie industry and have directly influenced and inspired real-time fire rendering, including this paper. Macrolevel behavior of fire is characterized by wind fields, temperature and moving sources and is currently processed on the CPU while micro-level behavior like turbulence, flickering, separation and shape is created on the graphics hardware. This framework provides a set of tools for level designers to wield artistic and behavioral control over fire as part of the scene. The resulting system is able to scale well, to use as few processor cycles as possible, and to efficiently integrate into an existing production environment. We present performance statistics and assess the feasibility of achieving interactive frame rates within a 3D engine framework...

2019

We present a method to create animations to express movement of volumetric smoke by compositing still images of computer graphics (CG) with a dynamic luminance information (DLI). Volume rendering is one of the rendering methods considering absorption and scattering of light by a medium involved in the air such as smoke. It can express smoke more realistic than normal rendering, but it takes a lot of time to render smoke CG animations. Thus, we express smoke motion of the animation created using volume rendering by combining a still image by normal rendering with DLI. We have experimented to compare perceptual quality of animations created by our method and normal volume rendering. We use image quality evaluation index and questionnaire for evaluation of perceptual quality. Experiment results show that our method can shorten the creation time and create animations keeping perceptual quality of animations using volume rendering.

Computer Graphics Forum, 2013

We propose various simulation strategies to generate single-frame fire effects for images, as opposed to multiframe fire effects for animations. To accelerate 3D simulation and to provide a user with early hints on the final effect, we propose a 2D-guided 3D simulation approach, which runs a faster 2D simulation first, and then guides 3D simulation using the 2D simulation result. To achieve this, we explore various boundary conditions and develop a constrained projection method. Since only the final frame will be used while intermediate frames are abandoned, earlier intermediate frames can take larger time steps and have large noise applied, quickly generating turbulent flow structures. As the final frame approaches, we increase the flow quality by reducing the time step and not adding any noise. This adaptive time stepping allows us to use more computational resource near or at the final frame. We also develop divergence and buoyancy modification methods to guide flames along arbitrary, even physically implausible, directions. Our simulation methods can effectively and efficiently generate a variety of fire effects useful for image decoration.

ACM Transactions on Graphics, 2002

We present a physically based method for modeling and animating fire. Our method is suitable for both smooth (laminar) and turbulent flames, and it can be used to animate the burning of either solid or gas fuels. We use the incompressible Navier-Stokes equations to independently model both vaporized fuel and hot gaseous products. We develop a physically based model for the expansion that takes place when a vaporized fuel reacts to form hot gaseous products, and a related model for the similar expansion that takes place when a solid fuel is vaporized into a gaseous state. The hot gaseous products, smoke and soot rise under the influence of buoyancy and are rendered using a blackbody radiation model. We also model and render the blue core that results from radicals in the chemical reaction zone where fuel is converted into products. Our method allows the fire and smoke to interact with objects, and flammable objects can catch on fire.

2008

We propose a method for real-time photorealistic stereo rendering of the natural phenomenon of fire. Applications include the use of virtual reality in fire fighting, military training, and entertainment. Rendering fire in real-time presents a challenge because of the transparency and non-static fluid-like behavior of fire. It is well known that, in general, methods that are effective for monoscopic rendering are not necessarily easily extended to stereo rendering because monoscopic methods often do not provide the depth information necessary to produce the parallax required for binocular disparity in stereoscopic rendering. We investigate the existing techniques used for monoscopic rendering of fire and discuss their suitability for extension to real-time stereo rendering. Methods include the use of precomputed textures, dynamic generation of textures, and rendering models resulting from the approximation of solutions of fluid dynamics equations through the use of ray-tracing algor...