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Permalink Reply by Scott Hsu-Storaker on October 12, 2007 at 12:01pm

I think this is the perfect place to start, and was actually the impetus for me wanting to start this sub-group. I was really gung-ho about a year ago when I started exploring second life, thinking I could start creating all of the wonderful things I knew how to make with my skills in standard 3D programs. I ended up being frustrated, though, with the prim creation tools and wished for something better. Maybe we could start this group by creating on ongoing list of what VWs take what kind of model formats and how to get our stuff into them. I facilitate a group that has a large number of models we give away and would love to be able to donate them to more communities.

I'll start.
World: Multiverse
Model Format: OGRE .mesh format
How to make your models: Well supported exporters for Max and Blender with standard model types
Notes: Seems promising in allowing user created content, but you might need skilled developers to partner with.

World: vSide, Doppelganger
Model Format: Torque .dts format
How to make your models: Well supported exporters (with extensive tutorials to boot) for Max, May, Milkshap, and Blender
Notes: They do not seem to allow user created content, is this true?

Scott

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Permalink Reply by Gary Mc Ginty on October 12, 2007 at 12:46pm

Hi Scott,
good idea,
we are just finished the VWC in San Jose.
we will compile a list of the 3D VW and the different file formats we found out about here over the next while
and from what 3D programs these files can be exported from,
regards,
Gary

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Permalink Reply by Scott Hsu-Storaker on October 12, 2007 at 5:01pm

A list like this one would be awesome.

World: Activeworlds
Model Format: renderware .rwx,
How to make your models: Standard formats can be converted with Accutrans
Notes: Not sure what the limits are.

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Permalink Reply by Glenn Gunhouse on October 13, 2007 at 8:02pm

Hi, I'm new. Pleased to meet you.
I build 3d environments with Blink 3D. These environments (I hesitate to call them "worlds" because they are small) are embedded in web pages as part of a web site hosted on a regular web server. There is no common world-space of the sort you find in Second Life, Activeworlds, etc., so, I wouldn't know what to put in the "World" field of the Blink 3D record. I can tell you that the model format is OGRE .mesh, which, as noted above, can be exported from various modellers. I use AC3D and Blender, then Gile[s] for lighting, and the Gile[s] OGRE exporter to produce the final models for use in Blink.

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Permalink Reply by Glenn Gunhouse on October 14, 2007 at 10:40am

It might also interest you to know that, since it is possible to export from Sketchup to OGRE .mesh format, some users of Blink (including me) sometimes get models from Google's 3D warehouse, convert them from Sketchup to .mesh, and then add them as assets to our Blink environments.

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Permalink Reply by Scott Hsu-Storaker on October 15, 2007 at 1:01pm

Hi Glenn,
Thanks for the reply. I would love to see your work in action -- the screenshots I saw on your site look great. Blink 3D looks like a great tool for where I used to work which had thousands of stores that needed to be re-designed each season. That sort of a closed network would be useful for an internal review process of environments.

Also, if you ever need any outdoor urban models, our project has a bunch of them ready to go -- lowpolycoop.com which are easy to export to .mesh.
Scott

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Permalink Reply by Dan Johnson on October 14, 2007 at 11:57am

I agree with your desire to import models from other applications but one of the things you will run into is that many of the model related issues are related to platform limitations. In SL, the capabilities of the SIM place some pretty extreme limits on what you can include in a model. As an example, vehicles are limited to 31 primitives unless you attach the primitives to the avatar. There are also limits to the number of primitives that can be linked and the distance between them. Free form meshes are not really supported in the same manner that most high level modeling tools use. Bottom line is that the servers need serious upgrades in order to handle the more complex models. It's not just an issue for parsing data formats. Maybe one day SL will open source the server code and we can all help fix the SIM issues. SL grinds most CPUs down quite a bit so with more complex models, the CPU and GPU loading becomes even more of an issue. I personally believe that custom hardware is needed to improve client/server performance. Delivering 3D content and multimedia content in a virtual environment takes some serious processing power. Software solutions alone won't get the job done...

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Permalink Reply by Scott Hsu-Storaker on October 15, 2007 at 12:53pm

Hi Dan,
Thanks for the great reply. Have you (or anyone else) ever used sculpted prims in SL? They had not arrived yet when I first tried learning how to build in SL last year and at first look, they seem like they could be useful. But, I imagine, their limitations show up pretty quickly.

On a similar note, how do these other worlds which use more standard mesh formats (and lighting and more complex materials) handle the stresses on the systems? Do they rely on the fact that traffic is lower?
Scott

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Permalink Reply by Glenn Gunhouse on October 15, 2007 at 2:11pm

I can only speak for Blink, but it requires the same sort of strategies as other virtual-world platforms. Too many objects, too many polygons, too complex lighting, too many avatars visiting, can cause it too get sluggish. The OGRE rendering engine that Blink uses is very good. It has its own techniques for maximizing frame rates (occlusion, levels of detail, etc.). In a complex environment, I have to do additional things as well. For example, since dynamic lighting can slow things down quite a bit, I use pre-calculated light maps for most things, and only use "live" lighting on avatars. I can also limit the range within which avatars can be seen. Theoretically, I can also limit how many polygons an avatar can have, or force visitors to adopt simpler avatars. Complex environments can be made of parts. Interiors of buildings can be loaded only when the building is entered, and unloaded when they are left behind. Managing all these things for a very complex environment is very difficult. I simplify things for myself by keeping the environment small, and linking it to other similar environments. The "world" is therefore a collection of linked web sites, instead of one giant 3D environment.

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Permalink Reply by Dan Johnson on October 15, 2007 at 7:09pm

Hey Scott,
I downloaded the sculpted prims instructions for Blender but had a hard time getting excited about it. It will allow a little more creativity in SL but not much. It's a far cry from a free form mesh and the tools that we are used to working with in commercial and open-source modeling tools. Even if we have to be restricted to a limited set of primitives it still would be nice to be able to import models. I'm planning to include a broad range of 3D formats in my project but at some point I'm sure there will be licensing issues that I have to address.

Glenn's comments are a good summary of the techniques that can be used to reduce the complexity of a 3D scene but it comes at the expense of detail. Personally, I like highly detailed models with rich textures, animation, multiple light sources, and physical effects. I absolutely hate the prim limits in SL . That's why land sells and contributes so much to the over-all economy there. SL is a nice start but I really feel hobbled there when it comes to modeling.

Glenn has hit on one of the schemes that I think will work well. Cross-linking smaller 3D environments in a way that it appears to be one continuous environment. SL attempts to implement this by allowing you to cross between SIMs but the performance issues make for a horrid experience, especially if you are in a high speed vehicle or aircraft. Your model actually comes apart and leaves "prim trash" in the SIMs. Not good... My design will make use of multi-threaded Java processes and peer-to-peer sharing to handle the linkage. The algorithm uses proximity detection to calculate the probability that an avatar will cross a virtual boundary and begins caching assets to ensure a smooth transistion between environments. I'm sure there are other ways to address the problem but the solution depends on the limitations of the rendering engine and the GPU.

Anyone out there have any 3D file format parsers that they are willing to open-source? I'll be releasing the Java code for my modeling APIs as I complete them. Perhaps we could start a project on SourceForge to establish a library of 3D parsers. Just a thought, would be interested to see what others think...

Dan

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Permalink Reply by Glenn Gunhouse on October 15, 2007 at 8:12pm

Those interested in making models specifically for Second Life might appreciate AC3D's sculpted prim maker. http://www.inivis.com/secondlife.html

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Permalink Reply by drOffset on October 20, 2007 at 1:37pm

Hi Everyone, I'm starting to do some related articles on my blog, http://droffset.blogspot.com . I'll add to the list here if that's ok.

formats: obj + bvh (obj for the object, bvh is a motion format)
Used in Second Life, Ogoglio, and openCroquet(as far as I know)
Notes, there's not a lot of information about how the model and animation are connected in the browser.

COLLADA
file interchange format
Used as a intermediary to convert to Multiverse's format
Many of the 3D warehouse models can be downloaded as the collada format

Sculpted prims
blah. blech. similar to doing 3D modeling with a sausage.

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