Jun 27 2008

I am not a number, I am a free avatar! – OpenSim post 0.5.8 svn_5234 ODE

Published by at 1602h under OpenSim

With many thanks to the globe-spanning OpenSim community, I have seen the error of my sourcing ways and replaced a version of Open Dynamics Engine that I had compiled on my Ubuntu x86_64 system, on 20080220, leaving the product of that effort, libode.so, up at /usr/local/lib which seemed well and good at the time. As things have evolved, ODE was brought into opensim-libs svn at some point after the last change log entry at 20080328. I was happy to find that ODE was included in the OpenSim svn, and turned on the physics engine in my OpenSim.ini configuration file.

Where I went wrong was not clearing out the library I’d compiled back in February, because that directory was getting sourced before my latest version in each of the nine OpenSim svn builds I’ve made since April. Last night, Dahlia helped me get focused on fixing the problem that I was having and she demonstrably was not. Teravus cleared up that my issue was squarely that of ODE and nothing but ODE, and Nebadon pointed me to exactly the updated documentation that I needed to build my own new ODE for the first time since I’d migrated the test server to Ubuntu 8.04 from 7.10.

In the process, I’ve learned to expect more efficient memory usage than I’d been understaning. I had written to Nebadon that my 40 regions were using 1.4 GB of memory, but once I had to start killing processes after every sphere I’d rez, I saw that the processes that I was killing were all less than 900 MB memory. And now, with ODE, MySQL region and asset storage, and 40 regions, I get OpenSim console statistics showing 194 MB “Allocated to OpenSim”.

Here is a video of what the old ODE (20080220) did with a really big cube (25-meter sides dropped from 500 meters)

After compiling ODE from the OpenSim-libs/unmanaged trunk, and adding a few build tools to my server, I got a fresh libode.so that was 3.7 MB rather than the 3.1 MB that was distributed with svn 5234. I did not tweak any compile flags as this was from OpenSim folks’ favored setup. After ODE was working, I slept well and awoke very optimistic about my prospects for getting a demonstration public-facing by end of July. I also have enjoyed testing the performance of ODE, particularly after Dahlia shared some time on her Dev server at OSGrid.org.

With ODE running, certain physical prim movements can consume plenty of CPU cycles, and even with two avs and some complex mesh interactions, there can be striking lag. So with my own regions working once again, I wanted to see how that looked, and I was inspired by the 1967 TV series The Prisoner to create an oblate spheroid (5 m by 5 m by 4 m) as a physical prim to roll after Ruth. The first of my efforts was shot here, and as you can see, I used Rover’s Dutch cousin, as orange was much easier to see than the original Welsh white Rover.

Finally, to impart a sense of drama, I textured Rover with a menacing City of Berkeley sewer manhole cover, and finished the celebration of ODE with a long take including several region crossings and a pleasant sunset hue from Windlight. As I hope is clear with this video, OpenSim has really come a long way in the past couple of months!

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