Archive for July, 2012
We want to draw your attention to the following SIGGRAPH 2012 paper, called “Mass Splitting for Jitter-Free Parallel Rigid Body Simulation” by Richard Tonge (NVIDIA), Feodor Benevolenski (NVIDIA) and Andrey Voroshilov (NVIDIA).
We present a parallel iterative rigid body solver that avoids common artifacts at low iteration counts. In large or real-time simulations, iteration is often terminated before convergence to maximize scene size. If the distribution of the resulting residual energy varies too much from frame to frame, then bodies close to rest can visibly jitter. Projected Gauss-Seidel (PGS) distributes the residual according to the order in which contacts are processed, and preserving the order in parallel implementations is very challenging. In contrast, Jacobi-based methods provide order independence, but have slower convergence.
We accelerate projected Jacobi by dividing each body mass term in the effective mass by the number of contacts acting on the body, but use the full mass to apply impulses. We further accelerate the method by solving contacts in blocks, providing wallclock performance competitive with PGS while avoiding visible artifacts. We prove convergence to the solution of the underlying linear complementarity problem and present results for our GPU implementation, which can simulate a pile of 5000 objects with no visible jittering at over 60 FPS.
As you may see, one of the main features of this solver is fast and stable simulation without jittering, even with high number of contacts.
Thanks to Jesse Stiller for the link.
Ageia PPUs are not recognized by latest PhysX System Software releases, but with a bit of work you will be able to play every game with hardware PhysX acceleration (assuming you have NVIDIA GPU as well), without necessity to reinstall PhysX drivers for each title.
Please note that only certain games (based on PhysX SDK below 2.8.3) are featuring PPU support. Even following this guide, you can't force latest titles like Batman: Arkham City to utilize your PPU.
- How to put the Demos back in the PhysX Control Panel: Video Guide
- Ageia PhysX Cards: are they still worth it ?
Keep an eye on MohawkADE’s channel, as more interesting videos and reviews are coming soon !
NVIDIA has presented updated PhysX SDK 3.2.1, which includes many bug fixes and small improvements in comparison to initial SDK 3.2 release.
Update: PhysX SDK 3.2.2 is available
|PhysX SDK 3.2.1 – Release Notes|
- Added GRB hooks for APEX 1.2.1.
- Some incorrect usages of __restrict have been fixed.
- A crash when the user’s code had FPU exceptions enabled has been fixed.
- A rare crash on Win64 has been fixed.
- Removed no longer needed RapidXML library from distribution.
- Binary serialization can now save the names of actors and shapes.
- Removed a RepXUtility.h reinterpret_cast compile warning that happened on some platforms.
- Fixed a spurious overlapping read/write error report when using simulation call backs in checked builds.
- Clarified documentation regarding use of eSEND_SLEEP_NOTIFIES flag.
- Clarified documentation regarding using different CRT libraries.
- Removed some confusing statements about meta data from the documentation.
- Updated PsPool, PsSort so they can use the user allocator.
More interesting papers from PhysX research team and Dr. Matthias Müller-Fischer, PhysX SDK Research Lead in NVIDIA.
First paper, called “Mass-Conserving Eulerian Liquid Simulation“, present latest advancements in hybrid fluid solver development – a topic of active research for past several years [previous work].
We present a GPU friendly, Eulerian, free surface fluid simulation method that conserves mass locally and globally without the use of Lagrangian components. Local mass conservation prevents small scale details of the free surface from disappearing, a problem that plagues many previous approaches, while global mass conservation ensures that the total volume of the liquid does not decrease over time. Our method handles moving solid boundaries as well as cells that are partially filled with solids. Due to its stability, it allows the use of large time steps which makes it suitable for both off-line and real-time applications.
We achieve this by using density based surface tracking with a novel, unconditionally stable, conservative advection scheme and a novel interface sharpening method. While our approach conserves mass, volume loss is still possible but only temporarily. With constant mass, local volume loss causes a local increase of the density used for surface tracking which we detect and correct over time. We also propose a density post-processing method to reveal sub-grid details of the liquid surface.We show the effectiveness of the proposed method in several practical examples all running either at interactive rates or in real-time.
At some point this research may be made into new APEX module, according to our information.
NVIDIA has officially presented new version of PhysX System Software – 9.12.0613.
- Includes the latest PhysX runtime builds to support all released PhysX content.
- Changes & fixed issues in this release
- Performance updates for various applications including Batman Arkham City, Alice 2 and other 2.8.4 applications.
- Supports NVIDIA PhysX acceleration on all GeForce 8-series, 9-series, 100-series, 200-series, 300-series, 400-series, 500-series, and 600-series GPUs with a minimum of 256MB dedicated graphics memory. Note: Some applications may have higher minimum requirements.
PhysX System Software 9.12.0613 can be downloaded from NVIDIA website.