For being such an iconic and easy to understand phenomena, Rainbows have long been difficult to simulate mathematically. The recently meme’d double-rainbow has long been missing from most simulations, but thanks to some recent discoveries by researchers at UC San Diego, they may now be simulation reality.
Until now, most simulations of rainbows had assumed that water drops are spherical, which isn’t true for large rain drops, Laven says. In this paper, researchers have adopted a completely different approach and developed a more realistic model to recreate rainbows, he says.
“The simulations shown in this paper offer the prospect of a better understanding of real rainbows,” Laven says. “I hope that the next step will be to use these new techniques for a systematic investigation of rainbows caused by realistically shaped rain drops.”
AMD is pushing into the GPU-compute space hard with systems like Fusion, and has now managed to get their FirePro discrete card certified for OpenCL acceleration of the Abaqus Finite Element solver.
“Many of the tasks that used to take a full day to complete can now be done in about half that time with GPU compute, saving engineering time and resources during product research and design, and reducing overall time to market,” said Sandeep Gupte, general manager, AMD Professional Graphics. “With SIMULIA’s latest realistic simulation software, which is compliant with OpenCL standards, engineers can achieve precise results in their design analysis with minimal hardware limitations.”
First we showed you how you could modify actors in live video with MovieReshape, now we can dynamically regenerate their clothing as well thanks to work by Carsten Stoll of the Max Planck Institute in Germany. They’ve generated 3D laser scans of actors in costume and motion-tracked the silhouette and skeletons. Then analyzed the cloth and can map it onto newly detected skeletons in new video, allowing them to change clothes.
According to Stoll, the results are extremely realistic. When he and his team showed 52 people a video of a woman dancing in a skirt alongside a reconstruction that his software had produced, the majority of viewers said that the reconstruction was “almost the same” as the original.
They talk a lot about using it in Video Games, but I believe the technology would probably first be used in VFX. In fact, they’ve got Andy Lomax at The Foundry looking at it right now.
“This is exactly what people like me want,” says Andy Lomas, a software developer who produced digital effects for the film The Matrix and is based at computer graphics firm The Foundry in London. “I want to be able to capture the fundamental nature of an actor’s clothing, but also have the freedom to change the way he or she moves.”
This technology will be unveiled at SIGGRAPH Asia.
NextLimit may have a competitor to their popular RealFlow CFD package coming up soon in the form of a new tool called Slipstream FX from canadian company Exocortex. They use an automatic adaptive tetrahedral mesh and claim that their simulation algorithms, while currently only marketed to the movie industry, are suitable for use in real-world engineering problems (after some rigorous validation testing, of course).
Normal CFD meshes must be aligned with fluid boundaries and flow fields to produce accurate results. This technique requires much fussing by the analyst to get the mesh right. When the flow-field changes, as it does unsteady flows, analysts must revise or recreate the CFD mesh.
Exocortex’s approach enables the tetrahedral mesh to be quickly and automatically refined and redefined in regions where the flow velocity changes rapidly. Consequently, the software is able to model complex phenomena such as breaking waves and water sloshing in a tank.
The rapid refinement is made possible by dividing the mesh-generation and CFD solution among multiple processors.
Over at the VizWorthWatching blog (run by some CEI staff), they have an article on an analysis of the underbody of the 1997 Camaro SS. After establishing a baseline with a classic wind tunnel, the simulated the effect with StarCCM+, and then exported the data for use in EnSight.
Some nice pictures, with a few details on the process, over at their site.
A master’s thesis by Øystein Krog integrates into the open-source Ogre3d system to provide CUDA-accelerated smoothed particle hydrodynamics.
This work is part of my masters thesis in Computer Science at NTNU (Norwegian University of Science and Technology). I have created a SPH library that uses the power of the GPU (through CUDA) to simulate fluids with extremely high performance (“real-time”). In addition I have created a small demo application that uses Ogre to render the simulation interactively. The application (and library) supports simple “wall” boundaries as well as “terrain” boundaries. The terrain is rendered using Ogre’s excellent new terrain component.
The results are impressive, and I almost swear I saw this at the SIGGRAPH Real-Time theater. If not, then something very similar. The ability to simulate thousands of particles in real-time is one of those very GPGPU-like problems.
The demo at SIGGRAPH first simulated the particles, then used a multi-pass rendering technique to make the result looks like real semitranslucent water.
Jan Vlietinck has published a simple 200x200x200 fluid simulation that simulates and renders the result using the new DirectX11 DirectCompute GPU acceleration systems.
The calculations make use of a well known scheme of velocity advection, Jaccobi pressure solving and making the velocity divergence free by subtracting the gradient of the pressure.This is the so called Semi-Lagrangian scheme. A more accurate solver makes use of the second order MacCormack technique. The simulation makes use of the latter. However it makes the simulation unstable and introduces artifacts. Limiting generated extremes can fix this, unfortunately I was not able to get this working, so the simulation runs without limiters, still the result is some visual interesting turbulent behavior.
The amplitude of the speed vectors are visualized. To make a 3d rendering, a simple ray maximum projection is used. This shoots rays through the volume searching the maximum speed along the ray. With a linear interpolation the speed is given some color.
Researchers at Wright State University have been closely analyzing the flight patterns and aerodynamics of dragonflies in attempts to recreate the effect in a computer simulation. After several years of painstaking research, they’ve finally developed a working simulation that they visualized using TecPlot.
“The visual results showed the exact motion of a dragonfly taking off, including its body motion and wing deformations,” says Dr. Dong. “Now, by varying our validated mathematical model, we can begin to understand with great confidence how a dragonfly manages its wings to create the forces needed to lift its body up under a variety of conditions. Next, we need to repeat the process for other stages of flight like hovering, maneuvering, and landing.”
See videos of their simulation results after the break.
Cryosurgery, placing cryoprobes in cancerous tumors to instantly freeze and kill them while still inside the body, is a new technique to fight cancer, but training new surgeons in this technology is difficult because of the potential to destroy healthy tissue and cause other potentially deadly complications. Carnegie Mellon Mechanical Engineering professors Yoed Rabin and Kenji Shimada have created a virtual surgery training simulation with the help of a $1.3Million grant from the National Cancer Institute to make training much safer and easier.
Dr. Shimada, in a news release, said the process will allow surgeons to place probes without risk to patients, visualize frozen regions with intuitive 3D computer graphics and benchmark their performance with hundreds of cases stored in a database. “It is a motivational and effective way of learning and improving their surgical skills,” he said.
The above image has been popular on the internet this week, the mysterious blue and white spiral hovering over the horizon of Norway. Alien invasion? Death ray satellite? Well, Doug Ellison ran computer simulations showing the effect could have come from a misfired missile tumbling through the sky (creating the white spiral of smoke) and leaking fuel (the blue spiral), and it probably came from Russia based on the region. Russia initially denied it, but has just recently changed their tune:
The jinxed Bulava intercontinental ballistic missile failed at the third stage after being test-fired from a submarine in the White Sea, Russia’s military said.
They still won’t claim that the lights are from their rocket, but given the circumstances it seems likely.
See Doug Ellison’s simulation and video of the actual lights after the break.
For being such an iconic and easy to understand phenomena, Rainbows have long been difficult to simulate mathematically. The recently meme’d double-rainbow has long been missing from most simulations, but thanks to some recent discoveries by researchers at UC San Diego, they may now be simulation reality.
AMD is pushing into the GPU-compute space hard with systems like Fusion, and has now managed to get their FirePro discrete card certified for OpenCL acceleration of the Abaqus Finite Element solver.
First we showed you how you could 
NextLimit may have a competitor to their popular RealFlow CFD package coming up soon in the form of a new tool called Slipstream FX from canadian company Exocortex. They use an automatic adaptive tetrahedral mesh and claim that their simulation algorithms, while currently only marketed to the movie industry, are suitable for use in real-world engineering problems (after some rigorous validation testing, of course).
Jan Vlietinck has published a simple 200x200x200 fluid simulation that simulates and renders the result using the new DirectX11 DirectCompute GPU acceleration systems.
Researchers at Wright State University have been closely analyzing the flight patterns and aerodynamics of dragonflies in attempts to recreate the effect in a computer simulation. After several years of painstaking research, they’ve finally developed a working simulation that they visualized using TecPlot.
Cryosurgery, placing cryoprobes in cancerous tumors to instantly freeze and kill them while still inside the body, is a new technique to fight cancer, but training new surgeons in this technology is difficult because of the potential to destroy healthy tissue and cause other potentially deadly complications. Carnegie Mellon Mechanical Engineering professors Yoed Rabin and Kenji Shimada have created a virtual surgery training simulation with the help of a $1.3Million grant from the National Cancer Institute to make training much safer and easier.
The above image has been popular on the internet this week, the mysterious blue and white spiral hovering over the horizon of Norway. Alien invasion? Death ray satellite? Well, Doug Ellison ran computer simulations showing the effect could have come from a misfired missile tumbling through the sky (creating the white spiral of smoke) and leaking fuel (the blue spiral), and it probably came from Russia based on the region. Russia initially denied it, but has just recently changed their tune:
VizWorld.com 
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