Army to release browser-based viewer for OpenSim

Editor’s note: This article was updated on 1/27/2023 to remove dead links and  links to malicious sites.

An OpenSim viewer that runs in a regular web browser has long been at the top of most-wanted lists for OpenSim users. And the U.S. Army is stepping up.

This fall, the U.S. Army’s Simulation & Training Technology Center will release an HTML5 viewer for its MOSES project.

Douglas Maxwell
Douglas Maxwell

“The first version of the web client will be view only,” said Douglas Maxwell, the center’s science and technology manager for virtual world strategic applications. “Understanding the plumbing for what it would take to create a web client was a tremendous undertaking.”

The new web-based viewer should be accessible on any device that supports HTML5 and WebGL, he added.

“We have not focused on optimization yet, so I do not recommend the early users try to connect using an older iPad or smartphone,” he said.

The new viewer uses the Babylon JavaScript framework, used for building 3D games, and which has complete support for “full-immersion stereoscopic viewing and virtual reality head gear” according to the framework documentation.

For an example of what’s possible in the Babylon framework, check out this Assassin Creed Pirates demo.

Still from Assassin's Creed Pirates demo by Ubisoft.
Still from Assassin’s Creed Pirates demo by Ubisoft.

And the graphics capabilities are ahead of those of existing OpenSim viewers, Maxwell said.

“We believe it will be easy to convince the users to switch given that the new system will look so much better and the interface will be familiar,” he said.

“In our investigation, we were able to create stunning graphics with low overhead on the client hardware,” he said in a comment on a Google Plus post by Talla Adams about moving beyond the Second Life paradigm. “Further, the MOSES web client will be tunable, meaning we can detect what kind of client hardware you are using — mobile, laptop, desktop, GPU, etc… — and make sure you don’t have to draw a scene too heavy for your gear.”

The user interface will be customizable, as well, he said.

“Since this is all JavaScript, anyone can come along and change the way the UI looks for their grid’s needs,” he said. “It can be as simple or complicated as you like and even have different functionality based on the role of the user.”

Building tools will be added later, he said, and scheduled to be released in the second phase of the rollout next spring. Until then, creators will still need to have a third-party viewer such as Firestorm or Singularity.

Since OpenSim isn’t designed to communicate via the web, it requires a separate piece of software, what Maxwell calls a “data arbiter.”

It sits between the web viewer and the Halcyon server, the version of OpenSim used by the MOSES grid.

“We had to create a way to efficiently shuttle data between the Halcyon server and the arbiter using protocol buffers,” Maxwell told Hypergrid Business. “You can think of the arbiter as a new kind of alternate client manager.  This heavy responsibility will eventually be removed from the OpenSim server altogether, enabling scalability.”

The existing client manager, which works with Firestorm and other third-party viewers, will remain in Halcyon for the time being.

However, it will eventually no longer be needed as the build functionality moves to the web viewer. The way that building is handled will change as well, Maxwell said.

“We plan to leverage more of the PhysX engine’s capabilities,” he said, referring to the physics engine used on the MOSES grid. “The most noticeable impact to the build tools will be in a change to how linking objects works.  We will introduce masses, offset linkages, joint limits, spring constants, and more.”

The new viewer will be released as open source.

“It will work in Halcyon, but anyone can take it and modify it to work with their flavor of OpenSim,” Maxwell said.

Maria Korolov