[Opensim-dev] [Non-DoD Source] Re: PhysX vs. BulletSim vs. ODE (UNCLASSIFIED)

Sun Feb 7 18:13:24 UTC 2016

Classification: UNCLASSIFIED
Caveats: NONE

I've gotten a lot of DM's on the subject of testing & evaluation.  We appreciate your interest in the work.

The MOSES project set up a public redmine site a while back for you to monitor our progress and download latest code.  You can find the wiki here:
https://redmine.militarymetaverse.org/projects/opensim-physx/wiki

and the files area here:
https://redmine.militarymetaverse.org/projects/opensim-physx/files

The latest stable version is 1.05, but the brave can jump into the beta 1.1.  We also release our test scenarios as OAR files and the software design spec.

Please keep in mind that the chaotic nature of the OpenSimulator development process has prevented us from maintaining lock-step compatibility with the latest OpenSim code base.  Please review documentation and work from our GitHub OpenSim code base for your testing.  Should someone wish to volunteer to integrate or maintain a version of our PhysX module that is compatible with the latest OpenSim code, we would welcome the collaboration.

MOSES GitHub:  https://github.com/M-O-S-E-S

v/r -doug

Douglas Maxwell, Ph.D.
Science and Technology Manager
Virtual World Strategic Applications
U.S. Army Research Lab
Simulation & Training Technology Center (STTC)
(c) (407) 242-0209

-----Original Message-----
From: opensim-dev-bounces at opensimulator.org [mailto:opensim-dev-bounces at opensimulator.org] On Behalf Of David Saunders
Sent: Friday, February 05, 2016 8:08 PM
To: opensim-dev
Subject: Re: [Opensim-dev] [Non-DoD Source] Re: PhysX vs. BulletSim vs. ODE

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I am very interested in testing out the physics system.  But the big question is, is there any requirements past the basic opensim requirements to have it working on another grid?

On Fri, Feb 5, 2016 at 1:27 PM, Zadark Portal <zadarkportal at gmail.com < Caution-mailto:zadarkportal at gmail.com > > wrote:

        Hello Douglas
        Interesting progress report. Is there any timeline available for if or when others can configure and profile the system?
        Zadark

        On 5 February 2016 at 18:00, Maxwell, Douglas CIV USARMY RDECOM ARL (US) <douglas.maxwell3.civ at mail.mil < Caution-mailto:douglas.maxwell3.civ at mail.mil > > wrote:

                Thank you for your feedback, Michael.  As you know, the OpenSimulator is a very complex system.  It is very important for us to isolate as many variables as possible to present a responsible comparison analysis of the three engines.  Sean presented the performance of the engines with the OpenSim configured as "stock".

                You are absolutely correct, using the "UseSeparatePhysicsThread" flag does improve performance.  It is just one of the variables we are examining to determine the affect of the physics engine on the overall system.  Sean was reporting that there were significant increases in performance during the baseline testing.  By carefully and systematically changing the variables in the system, we can determine which variables have the most impact differentiation from the baseline as well as what affect each variable has on each engine.

                I realize this looks like tedious work, and it is.  However this approach allows us to profile and examine the code so that meaningful changes can be made for the better (not accidentally stumbling upon a combination of variables).    As an Enterprise level user, we need the ability to predict how the simulator will behave under different loads so we can plan and provision for different usage scenarios.

                In the very near future we will be releasing our distributed PhysX code as well.  This functionality will allow you to dedicate a separate server to the physics engine and scale it vertically as appropriate.  We can discuss the implications for scaled performance as well as tradeoffs in network performance at that time.

                Lastly, we have specific needs that BulletSim cannot accommodate.  The decision to choose PhysX for integration was done deliberately.  If you would like to join us at the MOSES office hours or contact me directly, we can discuss in detail.

                Have a great weekend.  v/r -doug

                Douglas Maxwell, Ph.D.
                Science and Technology Manager
                Virtual World Strategic Applications
                U.S. Army Research Lab
                Human Research & Engineering Directorate
                (c) (407) 242-0209 < tel:%28407%29%20242-0209 > ________________________________

                From: opensim-dev-bounces at opensimulator.org < Caution-mailto:opensim-dev-bounces at opensimulator.org >  [opensim-dev-bounces at opensimulator.org < Caution-mailto:opensim-dev-bounces at opensimulator.org > ] on behalf of Michael Emory Cerquoni [nebadon2025 at gmail.com < Caution-mailto:nebadon2025 at gmail.com > ]
                Sent: Wednesday, February 03, 2016 11:10 AM
                To: opensim-dev at opensimulator.org < Caution-mailto:opensim-dev at opensimulator.org >
                Subject: [Non-DoD Source] Re: [Opensim-dev] PhysX vs. BulletSim vs. ODE

                All active links contained in this email were disabled. Please verify the identity of the sender, and confirm the authenticity of all links contained within the message prior to copying and pasting the address to a Web browser.

________________________________

                I have had over 100,000 physical spheres in Bulletsim without a crash and was still able to log in, move around and erase all the objects and have performance go back to normal, you need to enable running it in its own Thread, to achieve this level of performance. to enable this feature in the [BulletSim] section of OpenSim.ini add :

                UseSeparatePhysicsThread = true

                On Wed, Feb 3, 2016 at 10:56 AM, Sean M <mondesire.sean at gmail.com < Caution-mailto:mondesire.sean at gmail.com >  < Caution-Caution-mailto:mondesire.sean at gmail.com < Caution-mailto:mondesire.sean at gmail.com >  > > wrote:

                        Greetings,

                        The MOSES Team has been working on integrating NVIDIA's PhysX physics engine into OpenSim. Once complete, this integration will give OpenSim grid administrators the option of selecting the new engine for their own worlds.

                        Prior to releasing the complete integration, the team has begun extensively testing and analyzing the engine's performance. We are pleased to report that PhysX significantly improves OpenSim's ability to support more physical objects than BulletSim and ODE. Our analysis ran under controlled and repeated testing (30 independent OpenSim executions per engine) that isolated physics engine related variables. Under these conditions, PhysX supported 86% more physical objects than BulletSim (the OpenSim default physics engine) before the simulation's performance starts to noticeable degrade. More specifically, before dropping below 9 simulation frames per second (SimFPS), PhysX supported 3,300 physical objects (AtvPrm), BulletSim 1,800, and ODE 200. The reported SimFPS did not use the correction factor; therefore, the highest frame rate was 11.33 frames per second. Attached is a graph of the performance of the three physics engines as 5,000 physical objects were generated in the simulation. All experiment details will be available in the 2016 proceedings of MODSIM World.

                        Again, we are very pleased with the result and believe everyone will benefit from the effort. An announcement will be made in a few days to indicate when the final integration code will be available on the MOSES public GitHub.

                        Thank you,
                        Sean Mondesire
                        MOSES Team

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                Michael Emory Cerquoni

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Classification: UNCLASSIFIED
Caveats: NONE