Jul 13 2008

OpenSim SVN_5411 first test visit to public 40-region standalone

Published by under Open Berkurodam,OpenSim

I’ve got the OpenBerkurodam sim running this evening and ran a few test visits to all the regions. I’m posting a video that is fairly mundane, unless you care to see what 40 region standalones are like at first. Bare terrain (all seamless real-world terrain at 1:1.024 scale) that I visit rather gingerly. I’ve experienced a problem that I have seen associated with MySQL storage of terrain, where if I’m twirling round my av or point of view, sometimes my client isn’t sent a patch or trench of terrain data in a way that gets textured with the generic terrain patch. The result is an ugly trench, some number of 4-meter blocks across or wide, that is textured transparently, and surrounded with non-matching lower-elevation terrain patches. If I hold still while the client is getting the terrain streamed, then it will all (almost) always texture up properly.

The video is near YouTube’s 10-minute limit, but only because it took me an average of 15 seconds to let each sim rez completely before flying over close to it. This was because I really wanted to avoid the transparent trenches.

If the embedded YouTube link below does not image, the URL is http://www.youtube.com/v/BZjB4kkmWfo

Please don’t expect a very exciting video, but for folks with their own OpenSim multi-region standalones, some of the exact ways that the customized terrain rezzes may prove diagnostic. If you don’t have use for this information,

I apologize for the restarted SL client at 3:15 into the video, as an annoying update popup for Sea Monkey browser interrupted the SL client’s reduced screen resolution, and this was caught by FRAPS. There are curious but not uncommon contortions of Ruth’s legs (despite being far above the surface) when crossing region boundaries. There are also a couple of cases in the video where one can see Ruth shot back to the center of the region, even as she was about to cross the next region boundary. This doesn’t seem to happen in a consistent enough way that I’ve figured out a pattern with it yet, but I’ve only seen it happen in the SVN since about 5350.

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Jun 01 2008

Getting Physical with OpenSim 0.5.7_4952 – ODE with 40-region Standalone

Published by under OpenSim

After learning how the terrain sculpties could be handled by Meshmerizer if running a physics engine like Open Dynamics Engine (ODE), I have taken a couple of weeks to proceed slowly, cautiously as I bulk up the demands on the hardware. After all, my original notion of doing large swaths of real-life terrain on a single standalone sim was based on loading that terrain into the regions then using only Basic Physics to reduce the load.

But in the months since I first started loading real terrain (starting with Mt. Tamalpais in 200710), truly phenomenal, awesome progress has been made in how efficiently OpenSim runs for me on Ubuntu/Mono. Sure, at new year 2008 my OpenSim test environment upgraded from a P3-800/1.5 GB Coppermine system to an E6550-3.4 GHz/4 GB system. But what was limiting last Fall was the chatter among the various regions, so that I could add more: 49, 81, 100 regions–but then the CPU load with no client logged in would hum up toward 70%, and running a physics engine would be a challenge with many fewer regions.

These days, that seems like a stone-age experience. The rate at which regions now load on startup is incomparably faster (even on the old Coppermine), and the chatter is almost nil–no clients logged in looks truly quiescent at 1% to 2% CPU. All this has emboldened my interest in trying ODE again. And that experience likewise is so much better. Time was, there was reason to visit the ODE site and build one’s own, and even then stuff could get strange. I was inspired by the videos that Nebadon posted showing many hundreds of blocks falling. But I experienced things like tripping over what felt like a singularity that shot my unfortunate avatar hundreds of meters into the air, bouncing like some tire that fell off of a jet after takeoff. That was then.

Now I see Ruth’s legs bend a little bit under the effects of gravity, but I do have 40 regions humming along in standalone with quiet-state CPU load of 2% to 5%. So I have plenty of reason to expect that I’ll be able to do this with the 40-region model, using terrain sculpties that are physical as long as they don’t tilt over against the terrain surface like they do in the SL Agni grid.

Video demo of Ruth narrowly avoiding getting squished by a 10-meter cube
If you’ve got the embed blocked, the link should be http://www.youtube.com/v/Jz9234jYbkw

My next goal for Open Berkurodam is to generate a new surface. I may have a good copy of what is called categorized or classified LiDAR data, where individual points in a cloud are tagged with an estimate of whether they are from bare earth, tree crown, rooftop, and such. This sort of LiDAR data should support the sort of grid that is not just bare-earth terrain, but actually has the proper size, shape, and height bump for every tree and building. This would be ideal for draping with the orthophotography, because within the limits of parallax that have been corrected in the orthoimagery, every building should sort of take shape on its own.

I don’t hold any fantasy that things will look properly immersive right on the classified LiDAR grid, but I have a sense that there will be enough detail to guide a reasonably accurate build with just a bit of training on the part of the builder to recognize their way past registration artifacts–where the bump from the LiDAR surface doesn’t align with the roof part of the orthoimage.

To bring this to a presentable stage, I hope to somehow have a live version of the 40-region UC Berkeley and vicinity 1.024:1 model with classified LiDAR surface on physical sculptie megaprims, on a public server by mid-July.

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