Sorry, but it’s not true. You can create a multiplayer environment only using Unity (even the free version).
You can learn how to do it reading my tutorials at:
http://www.dmu.com

Como você fala portugues ten tutoriais em português e inglês.
Um abraço,
Americo

That works also againts Opensimulator, with the modrex extension that allows to put extra data to the scene (for example client side javascript script references, which implement the UI for that app).

So AFAIK the paradigm in reX and Unity is the same. Still certainly is good for me too to actually test it.

Perhaps you will have the chance to take a look at the new reX stuff at some point too. The new Naail & Tundra SDK are in some ways similar to Unity — reX is sometimes described as an open source alternative to Unity 3d. In the sense that both are now generic engines with an extensible scene model, and where application code determines the user experience, instead of some hardcoded viewer & protocol feats like with slviewer. There’s a quite short & clear article that describes this, also discusses the plan of refactoring Opensimulator to have similar extensible scene model: https://github.com/realXtend/doc/raw/master/arch_article/simple.pdf

One difference perhaps is that reX, like SL & Opensim, is inherently networked: by default, every object (scene entity) that you create is shared and synchronized among all the participants. But there is also the option to create the entity LocalOnly, both on client and server side, which I’ve recently used exactly for a similar case than your traffic simulation: in our upcoming demo there is a fish game (again!), where you swim around as a little anchovy eating plankton. The planktons clouds are composed of several particle systems, and to ease network traffic, the individual particle systems (which finally include the particles) only exist on the client side. But the bigger cloud entities are shared, so all clients see them in the same area in the water, just not in exact same positions. This should work well enough for the multiplayer game. Also physics can be done on either side, or both.

A company that has been developing reX and doing projects with it recently made one project with Unity3d too, but is now making another using reX while developing core features there too — they also came back with nice ideas for improvements

I think Unity and many platforms are fun and useful to have, and believe that there is room for both closed, proprietary packages like Unity3d and for open source such as Opensimulator and realXtend.

For the scene editing side, reX currently differs from Unity so that we mostly bring in ready made scenes .. use e.g. Blender or Max as the level editor. And there is a project to make this integration tight, having custom VW authoring UI in Blender, with a real-time connection to the server (already works agains opensim+modrex!), https://sim.lorea.org/pg/groups/5/b2rex/ . Naali/Tundra does have in-world editing, asset views, property editor etc. too .. but quite rudimentary still.

I think it’s a very interesting question: what creation tools should be an in-world experience, and what are fine as offline? Even SL users use separate apps to draw textures I’m currently working on a simple waypoint graph / walk path editor myself — originally had the idea to author the paths in Blender and export, but after I made the first test walk path (for a NPC deer) with in-world tools (just placing invisible objects as walk targets), and has so much fun tweaking the path nodes live while the deer was walking, decided to instead do something that can integrate to the platform directly. Decided to do it, surprise surprise: browser based! Because we use js for game logic, so can use the same underlying js graph lib, and as the viewer embeds a browser (like slviewer does too), can use it ‘in-world’ too. Put a little proof of concept test up at http://www.realxtend.org/world/lvm/pathedit/editor.html and will continue work on it in https://github.com/antont/pathedit next week. As also Unity3d supports js, perhaps unity projects could use the same waypoint graph editor even 😮

I hope we’ll get cross plat interop going on in such high level things — the custom cameras that you mention are my prime candidate for that.

Thanks again for the interesting post, let’s see where we end up with all these developments going on

I get a similar feeling when I look at Unity 3D. A step closer to what the “professionals” use, or the look I am used to see in their finished work. To me Opensim is my sketch book a place where with no fuzz I can sketch an idea in a few minutes. Primitive maybe? It works for me. To get a really polished look in Opensim requires a bit more work and in the end will still look different to a “professionally” modelled scene. (To me Opensim/SL looks more hand crafted like shaping a piece of wood by hand instead of using a router or a lathe, (a look that most of the time appeals to me.) I like how Opensim and Unity 3D work together in the browser al la Tipodean. Laughing at your Blender comment ( I know that feeling well) I have tried Blender many a time, after having seen some stunning work made in Blender. I guess I have to try harder

I’ve looked at the Jibe system the other comments mention and it looks like a good way to ease the multi-user side of things. I’m still building and testing a single user scene in Unity. but I intend to bring it all in to Jibe once it’s ready.

You said: “…if you want to create a virtual world with Unity3D, you need a lot of extra engineering work.”

Yep. And that’s precisely what ReactionGrid’s Jibe platform does. Jibe is a framework that lets you build scenes in Unity and then make them part of a multiuser virtual world. You can visit my own multiuser Jibe world here on the web.

When you were animating your cars, did you use the free iTween tool to move them around? I’ve been playing around with iTween and find it very handy.

And if you’re interested in talking with other people exploring how to create multiuser worlds based on Unity, we’ve got a pretty active Unity3d-Jibe Google Group with lots of good discussions going on.