Physics Simulation Forum

Bullet 2.73 has been released, download from http://code.google.com/p/bullet/downloads/list

For 8192 fast moving objects on NVidia 8800 GTX, Intel Core 2 3Ghz: CUDA (btCudaBroadphase) 6ms, OPCODE Array SAP 37ms, Bullet dynamic BVH (AABB tree, btDbvtBroadphase): 12ms. When nothing moves, the CUDA broadphase still takes 4ms, whereas SAP and dynamic BVH (btDbvtBroadphase) are practically 0ms. For even larger amounts of moving objects (64k) the CUDA still performs fine, whereas SAP/dynamic BVH grind to a halt. This makes it a good candidate broadphase for environments with huge destruction.

• Check this forum topic to see what’s new

Thanks to everyone for feedback, bug fixes and improvements!

• Blender 2.48 has been released: http://www.blender.org/development/release-logs/blender-248/
• Maya Dynamica plugin next?

  

• Developing Games with Open Source Technologies: Full-day Tutorial
• Monday, September 15th Austin Convetion Center, Room 9C
• 11:00am - 11:50am: Tumbling, falling and breaking: Bullet open source, professional physics engine

Open source technologies bring cutting edge innovation, source code accessibility, rich community support, and a pricetag that can’t be beat to developers in every industry — including the online game industry. In this one day mini-track you will learn first hand from leading game developers and technology providers about open source game engines, tools, and server technologies that are changing the economics of online game development today.

• For more information, see http://www.austingdc.net/events
• UPDATE: you can download the PDF slides here (6Mb).

Download here

Apart from numerous bug fixes, this is new:

• Walt Disney Studios contributes their in-house Dynamica Maya Plugin for Bullet physics simulation.
• Check out the Dynama Maya Plugin instruction videos.
• This Dynamica Plugin is used in Disney’s upcoming 3D animated movie Bolt, for example in the peanuts shot below.
  Thanks to Nicola Candussi and Arthur Shek from Disney for this contribution!
• Several bug fixes and contributions related to inertia tensor, memory leaks etc.
  Thanks to Ole K and several other contributors.
• Added btCudaBroadphase in Extras/CUDA: some preliminary research into accelerating Bullet using CUDA.
  Thanks to the particle demo from the NVidia CUDA SDK.
• Updated CDTestFramework, with latest version of OPCODE Array SAP. See Extras/CDTestFramework
  Thanks to Pierre Terdiman for the update
• ForkLiftDemo has been finished, finally!
• Improved performance for btDbvtBroadphase.
  Thanks to Nathanael Presson again, for all his work.

Enjoy!

OLPC is hosting a Physics Game Jam in Boston from August 29 to 31.

This is a team based rapid game development competition based on creating a physics game for OLPC XO laptops in 48 hours. Remote entries are allowed, and there will be prizes for the winners. PyBox2D is the main physics library that will be used, but anything open source that will run on the XO is fine.

There will be programming workshops such as developing in Sugar, using PyBox2D, and integrating computer vision with physics, so prior experience is not a requirement.

There is more information on the OLPC Wiki: http://wiki.laptop.org/go/Physics_Jam

Registration is free, but donations are encouraged: http://olpcphysics.eventbrite.com/

We are visiting SIGGRAPH again next week.

Some of the Bullet/physics related activities:

• There will be a Bullet presentation at the Sony booth #521 (exhibition hall) Tuesday, Wednesday and Thursday from 14.15-14.45.
• We will do a short COLLADA Physics presentation at the COLLADA BOF, Thursday, 14 August | 4:00 pm - 6:00 pm | LACC - Room 511A.
• And present about Bullet integration in Blender at the Blender BOF, Monday August 11, ~3-4 PM, Convention Center room 501A
• Some physics enthousiasts will gather on Wednesday after the Jiggly Fluids session (at the exit door), around 6.30PM.

Hope to meet you there,
Erwin

Bullet 2.70 physics SDK is available for download now.

Some new Features

• First version of kinematic character controller (non-rigid body). See Demos/CharacterDemo
• Improved soft body collision detection, using convex clusters. Thanks to Nathanael Presson.
• Added btMultimaterialTriangleMeshShape, see MultiMaterialDemo
  Thanks to Alex Silverman for the contribution
• Performance improvements for btDbvhBroadphase, and basic textures/shadow support, thanks to Nathanael Presson
• Havok .hkx to COLLADA Physics .dae file conversion, see hkx2dae
• Various bugfixes, thanks everyone for reporting!

Feedback is welcome in the forum.

Enjoy

Tony Mullen reported that his new book Bounce, Tumble and Splash! Simulating the Physical World with Blender (Sybex) is out:

“The book covers all of Blender’s simulation functionality in depth including fluid, soft body, cloth, rigid body, particles, hair and much more. This is the first time much of this functionality has been documented in print, so I really hope that the book will help to give these powerful features a much wider audience.

I took a bunch of snapshots to give people an idea of how the books look inside and out, and you can check those out here:

http://www.flickr.com/photos/27828225@N04/sets/72157605715872127/

There’s also a teaser on YouTube I put up some time ago. By all means take a look to get an even better idea of what this book covers:

http://jp.youtube.com/watch?v=3du8ksOm9Fo

The book’s in stock at Amazon:

http://www.amazon.com/Bounce-Tumble-Splash-Simulating-Physical/dp/0470192801

I hope you enjoy the book!

Tony”

Phya is a C++ library, that was created as an expandable system for adding physical audio to a virtual world. Phya released as Open Source under the ZLib license.
Also included is a new demo for the Bullet dynamics engine.

Visit http://www.zenprobe.com/phya or discuss here.

+ Added split impulse support, penetration recovery won’t add momentum
+ cloth/soft body improvements: picking (pick and drag), tearing (click and release without mouse move), preliminary support for btSoftBody versus compound and concave trimesh
+ Added new btDbvtBroadphase, based on dynamic AABB tree. It has the capability to do view frustum culling and front-to-back traversal. See Extras\CDTestFramework for view frustum culling sample.
+ Enabled new btGjkEpa2 penetration depth solver, thanks to Nathanael
+ Provide access to all persistent manifolds for a given btBroadphasePair, see CharacterDemo for sample usage
+ Added linear and angular motor for btSliderConstraint
+ Add penetration depth test for convexSweepTest
+ removed several warnings for Windows build, thanks to Martijn Reuvers
+ Added Mac Cocoa Xcode project, thanks to TomorrowPlus
+ use collision margin of btBvhTriangleMeshShape for convexTest, Thanks to reltham for the contribution.
+ added custom memory allocator registration, thanks to Sly.

Download Bullet 2.69 from the Bullet repository at Google Code.