Jupiter Rowland

tl;dr: OpenSim is a 15-year-old, free-and-open-source Metaverse from before The Metaverse was cool. And it's the Mastodon to Second Life's Twitter.

So I've been talking about something called #OpenSimulator. But what is it, this OpenSimulator thing?

Let me start this way: Currently, lots of entrepreneurs, startups and trillion-dollar megacorporations are jumping onto the #Metaverse bandwagon. OpenSimulator has been driving that same bandwagon for over a decade already without almost anyone noticing.

Technically speaking, OpenSimulator (or #OpenSim in short) is a free, #OpenSource server application for virtual 3-D worlds that runs on Windows and Linux.

But it's somewhat like Linux: Technically speaking, Linux is a kernel. But everyone says that Linux is an operating system.

So in practice, "OpenSimulator" refers to a number of online worlds called "grids". Yes, a number. Not just one. No matter how many #VirtualWorlds you've heard of, you may not have heard of OpenSim yet. That's because it isn't made by a company with an advertising budget but pretty much entirely by its user community.

Metaverse before Meta, decentralised before Decentraland

Decentraland advertises itself as, quote, "the first fully decentralized world", end quote. This is far from true, but the #Decentraland makers probably don't know that themselves because they may never have heard of OpenSim.

In fact, OpenSim has been around for much longer than Decentraland, namely since 2007. And it has always been as fully decentralised as a virtual world could possibly be. OpenSim has several thousand (!) independent grids, every single one of them being run by someone else, some by companies, a few by foundations, most by private persons. To give you an impression, Hypergrid Business has a grid list that's nowhere near exhaustive, nor is it always up-to-date, what with grids shutting down and new grids being launched all the time.

The OpenSim core developers are someone else than the many grid owners again. The various client applications, a.k.a. viewers, are developed by someone else yet again. There isn't any one big entity, much less a profit-oriented company, that's in control of the entire OpenSimulator ecosystem.

But those grids aren't several thousand walled-garden worlds separated and isolated from one another. Almost all of them are interconnected in the so-called #Hypergrid. This means that you can have an avatar on one grid and visit an entirely different grid with that avatar. You can (usually) take your entire inventory with you, and you can (usually) even pick up things on other grids and take them back home with you.

OpenSimulator is as decentralised and federated as #Mastodon, as #Diaspora, as #XMPP, as #Matrix, as #email. And it has been for almost one and a half decades now. Decades; that's an eternity in the online world. The Hypergrid is the closest to a "metaverse" of separate but inter-connected virtual worlds that we've come to date.

And there are actually several grids and institutions in OpenSim that have been carrying the word "Metaverse" in their names since long before Facebook became Meta. There's the Infinite Metaverse Alliance with its Metaverse Depot grid. Alternate Metaverse is one of the biggest grids on the Hypergrid. Just to name a few.

So at no point has OpenSim jumped upon the Metaverse bandwagon.

Second Life, but free and open-source and distributed

If you came here from Mastodon or elsewhere on the Fediverse, let me describe OpenSim to you this way: OpenSim is to #SecondLife what #Mastodon is to #Twitter. The main difference is that OpenSim has still got 99% of Second Life's look-and-feel plus most of its functionality. That's because it literally is a Second Life clone.

Remember Second Life? Guess what: It's still around. It has been since 2003. Yes, that long. 2006/2007 was only the huge hype. Even if it has been around for that long, it doesn't look anything like back then anymore. People who come back to Second Life after they've been there during the hype for the last time are blown away by just seeing mesh avatars.

What made OpenSim possible was when Second Life made its official viewer open-source. Anyone could see Second Life's API. For one, this was used to create third-party viewers. But beyond that, Second Life's inner workings could be extrapolated from the API. This knowledge was used to develop a wholly new system for virtual worlds, essentially Second Life with no big corporation behind it, no meddling Lindens all over the place, none of Second Life's rampant commercialism, but otherwise the same. This system was named OpenSimulator and first released in 2007.

Shortly afterwards, an experimental grid named #OSgrid was created as a testbed for the development of OpenSim. About 15 years later, OSgrid is by far the oldest and biggest grid on the Hypergrid, the latter both in land area and number of avatars, while still being a testbed.

It was fairly easy for OpenSim to take off because it has been using largely the same viewers as Second Life ever since. This, however, also means that the development of OpenSim is closely linked to that of Second Life.

Bigger than you may think

Now you may believe that OpenSim is tiny because "nobody knows it". It isn't. Let's have a look at the April 2022 statistics on Hypergrid Business to estimate just how big OpenSim is. Estimate because even Hypergrid Business only knows the stats from fewer than 300 grids; thousands of mostly small grids don't report any stats. For comparison, here are March 2022 stats for Second Life.

For one, those under 300 grids reported a good 43,000 unique active users. That's nothing in comparison to Facebook or pre-Elon Musk Twitter. But Second Life hasn't gone over 55,000 active users this year either.

Okay, so OpenSim has fewer users than Second Life. But it has got a greater landmass.

A standard region in both Second Life and OpenSim is a square that measures 256x256m (that's 65,536m² or 78,380 square yards for you Americans or nine football fields for you Germans). Second Life reported some 27,400 of these standard regions in use. Meanwhile, those under 300 OpenSim grids reported about 100,000 regions. This is not a typo. One hundred thousand. That's more than two regions per user. OSgrid alone reported 36,500 regions, making this grid alone bigger than Second Life by one third. Now you know why it's much less likely to meet other avatars on the Hypergrid than it is in Second Life.

How can OpenSim have such a huge landmass? Well, that's because land is way cheaper on the Hypergrid than in Second Life. There are two reasons for this.

One is that OpenSim is largely uncommercial. Entire regions usually do cost money, but much much less than in Second Life. You only have to pay to support the operation of the grid which often is in the hands of private people. You usually do not have to pay employees, and you never have to pay investors or shareholders. There are commercial grids, but they're the exception, and yet, they don't tax sales like Second Life and #HorizonWorlds do. Most grids don't have any means of in-world payment whatsoever.

The other one is that OpenSim has got much much more space in general. Not long ago, Second Life actually almost ran out of space. Its grid can't grow much bigger. Land is scarce, therefore it's expensive. OpenSim, in contrast, will never run out of space. A grid can consist of several hundred million regions. The maximum landmass is limited by available CPU power rather than area. Even that can be increased by running one grid on several servers; OpenSim scales very well.

Your own Second Life

This is also the reason why there are so many grids: Anyone can run their own grid and attach it to the Hypergrid if they want to. OpenSim can be hosted on anything from rented professional Web space to a Windows laptop to a Raspberry Pi (although you probably shouldn't host parties with well-known DJs on a self-hosted, Raspi-based grid).

So not only are there probably more users with at least one region of their own than without one, but at least every tenth user may be a grid admin, considering that bigger public grids often have more than one admin.

OpenSim has taken decentralisation to its full extent, much like e-mail or XMPP or Matrix or Mastodon. If you don't like the grid you're on, you can move to someone else's grid, or you can start your own grid and be "your own Linden", so-to-speak.

There's a vision of commercial, corporate-owned virtual worlds joining into a Metaverse. This will never happen because these worlds will never be sufficiently compatible to one another. OpenSim's Hypergrid, in contrast, is a network of connected virtual worlds that's reality already now.

All without having to throw yourself at any one profit-greedy company. No crypto-currencies, no NFTs, no blockchain. OpenSimulator is the Metaverse for the people, run by the same people.