OpenSim reaches 95% compatibility with Second Life

According to OpenSim core developer Charles Krinke, there are 330 key functions in Second Life – and 300 of them have been fully implemented in OpenSim.

Of the remaining 30, half have to do with vehicle physics, he said.

These are the functions that allow virtual passengers to ride in virtual cars, for example, fly virtual planes, or race virtual horses.

Except for these functions, objects can be imported from Second Life to OpenSim, and work much the same way.

I’ve seen this for myself. Doors open and close, in OpenSim worlds, for example, just as they do in Second Life. My hair swings when I move my head.

I even have ducks swimming in my pond.

According to Krinke, animating objects happens through the use of scripts, and OpenSim supports the Second Life scripting language.

Except for those pesky vehicle physics scripts – and those are mostly done, he added.

“You can generally expect to get 90 percent of the functionality of a Second Life simulator,” he said.

Adam Frisby (left) and Charles Krinke (right), two of the core developers behind OpenSim.
Adam Frisby (left) and Charles Krinke (right), two of the core developers behind OpenSim.

The other major functions still missing from OpenSim are voice chats – as opposed to the typed kind of chats – and group functionality.

And I’ve seen all of these functions – vehicle physics, voice chat, and groups – being tested over the past few days.

In fact, according to Krinke’s fellow core developer Adam Frisby, the difference between OpenSim and Second Life is  no longer 5% but just 2%.

“It’s been narrowing recently,” said Frisby, who’s head of research and development at Shanghai-based DeepThink.

Is OpenSim about to catch up to Second Life in functionality? Kind of.

“The Second Life way is completely broken,” said Frisby.

Instead, the OpenSim developers have decided to maintain basic compatibility on the outside – -while building the inside from scratch.

As a result, the platforms can be compatible — the same browsers can visit worlds built on both platforms, he said, “without pushing ourselves into a badly-designed corner.”

For example, when Second Life can take thousands more processing cycles to carry out the same functions as OpenSim — and, in some cases, tens of thousands of cycles, said Frisby. “In that respect, emulating Second Life is not a good idea.”

OpenSim will maintain backwards compatibility with Second Life, he said, but cannot be used to move forward.

“OpenSim will continue to evolve,” Krinke agreed. “Not towards 100 percent compatibility with Second Life, but in a direction that all the contributors determine.”

There are already signs of this happening.

For example, Second Life uses a particular types of software to model real-world physics – how objects fall and how they collide with one another. The Second Life software is called Havoc.

“Which we don’t use,” said Krinke.

Instead, OpenSim uses the Open Dynamic Engine, another open source project. Havoc, by comparison, is proprietary. It costs money.

As a result of the different physics engines, objects will always behave just a little bit differently in OpenSim than in Second Life.

In addition, if particular grid operators don’t like the Open Dynamic Engine, they can swap in another one. Today, OpenSim has four physics engines that can be installed.

And if none of those suit – well,  you can write your own. OpenSim is open source. If you’re so inclined, you can tweak it to your heart’s content.

“All the development of OpenSim is based on the contributions of the folks that submit original authorship of source code,” he said.

A core team of contributors decides which additions make it into the core build, he added. Altogether, there are about two dozen programmers working on the platform, with another 150 people contributing patches.

That larger group includes engineers from Intel and Microsoft, from IBM, and from other places, he said.


One way that OpenSim is likely to stay different from Second Life is in its currency system.

On the Internet, every website decides payments on its own. Some online merchants take credit cards, some take PayPal, some use Google Checkout.

Building a currency system into the core of OpenSim would limit what individual grid operators would be able to do.

Second Life, by comparison, isn’t just a platform but also a content provider – and it has its own mechanism to ensure that it gets paid for its content.

Instead of comparing OpenSim to Second Life, Krinke suggested comparing OpenSim to Apache, the very leading Web server platform. Apache, which is also open-source, is modular, Krinke said. Owners of websites can plug in the modules they need.

OpenSim is similar in that operators can install different modules for payment, for voice, and for other functions.

Maria Korolov