realXtend Tundra and MeshMoon

It is some years since I experimented with realXtend, which originally spun out of the OpenSimulator community code base, but quickly added mesh capabilities, long before this became the norm in OpenSim and Second Life. The quality of the image from one of these early tests of realXtend version 0.1 by me in 2008 is shown below, and its far more detailed than the simplistic prim worlds allowed at the time in OpenSim and Second Life.


Test on locally hosted realXtend 0.1 on 22-Feb-2008

This blog post is to collect resources and web links as part of exploring the most recent version and the associated technology of a browser based viewer, Moonmesh, which may be relevant to future browser-based access to OpenSim. realXtend and Meshmoon are included in a list of enabling technologies which may be used in recent EU technology innovation bids (in September 2014) see for example this news blog post…

Hypergrid Business: EU offers $103 mil in tech funding; OpenSim web viewer might fit
, Maria Kolorov, 23-Sep-2014

Software and Documentation

The latest server side versions are called realXtend, the viewer client is called Tundra and there is a web-based client called WebTundra. Meshmoon is a platform for showcasing realXtend and related applications and technology.

Demonstration Worlds Accessible in a WebGL Browser

Using a WebGL and WebSockets capable browser such as Mozilla Firefox or Google chrome you can access a range of ready-to-run demonstrations without installing other software…

Image2 2014-09-30-Meshmoon-Lunar

The avatar does not appear to be customizable and is definitely NOT wearing the correct head gear for the Lunar surface!


Circus World Demonstration of Tundra

A “Circus” demonstration world is available to download at


The example on the web page did not launch for me, even after manually associating the Tundra file that should be used with the preinstalled Tundra .exe file. It simply reported that Tundra had started but no active scene was selected. However, with the realXtend Tundra client installed, I was then able to download and unzip the Circus demonstration example into a suitable location and open the CircusScene.txml (Tundra Scene File) within it which launches Tundra and opens at the entrance to the circus tent. There is no documentation I could find on installing and running the Circus demo within the web page or the zip file… so its difficult to know what you do next. The arrow keys do not move the viewpoint and none of the icons except the information “i” does anything I can see. The camera could be moved about with the mouse and spacebar and “C” did shift the viewpoint up and down. No avatar is visible.


Meshmoon 3D Model and Texture Formats

realXtend and Meshmoon use the OGRE 3D XML-based format for meshes (.scene, .mesh, .skeleton) along with a realXtend overall description (.txml). Converters, for example for Blender are available. See

Meshmoon Unity3D Scene Import and Robot Lab Example

A utility to export some parts of a Unity3D created world into Meshmoon is available here… along with a demonstration of such an export that can be run in a WebGL/WebSockets browser such as Firefox… via The demonstration does allow the usual avatar movement via the arrow keys, spacebar for jump, etc. and the movement of the camera with the mouse.


Meshmoon Rocket and 3D Spaces

The Meshmoon Rocket client allows access to a range of 3D spaces created by various Meshmoon users, including 3D spaces created for your own avatar and optionally opened publicly which gives access to others and is listed in the directory…


A 3D space can be created via the Meshmoon web site (in my example for avatar “Ai Austin” username: aiaustin) using the Meshmoon Education program (MEP) credentials – see below. This space is called “Ai” and can be “launched” via this Rocket URL




Experiments with adding content will follow.

Meshmoon Education Program

Support is offered to educators via the Meshmoon Education Program (MEP) supporting up to 100 accounts via a coordinator. I have signed up as the Coordinator on behalf of the Virtual University of Edinburgh. So I am point of contact for anyone within wanting to explore with a free 3D world at present. Contact me at

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5 Responses to realXtend Tundra and MeshMoon

  1. Stinkfist says:

    Apparently the script assets that uses are a bit outdated and hence f.ex. in-world chat is missing. You can find the LudoCraft Circus also in Meshmoon in fully working form.

  2. Jonne Nauhal says:

    Good article. We are are working on improving the avatar aspect of Meshmoon. This will most likely be replacing old realXtend avatars with FBX based avatars. The tricky part is getting those FBX avatars working in both native and web client, there are solutions but they require some effort on the code front. An intermediate step will probably be using Unity to export avatars with Meshmoon asset formats and go from there forward.

    We have been fighting with avatars a long time, tried all kinds of things like OpenAvatar, Collada based avatars and FBX based avatars over the years. I think for the whole modeling/artist ecosystem its best to go with FBX even if the tech is non open source. Blender, assimp and other authoring/conversion tools are getting better at handling FBX binary and text formats all the time. All major gaming engines afaik primarily use FBX for models and avatars (skeletons/animations) alike.

    When you are doing the content authoring remember that we are not OpenSim nor SL. There are no prims, just meshes. There are lot of sources nowadays to get meshes made even if you can’t model. Our asset library is quite limited and you won’t be able to build really nice stuff with them. I recommend checking out the Unity Meshmoon Plugin from the start and utilize it’s import and asset store functionality!

    Best Regards,
    Jonne Nauha
    Meshmoon Developer

    • bat says:

      Good notes.. thanks for that Jonne. I am using FBX models in other virtual worlds that are emerging and have experimented with export of entire mixed OpenSim prim and Collada mesh builds to Collada and 3DS and then inputting those to Unity3D and via an FBX converter to use elsewhere.

      The Tipodean converter can take an OpenSim Archive as an entire region and convert it to 3DS for use in Unity3D and via import/export in a normal 3D modeller to other platforms. See for example

      Interesting obsevations about avatars. Tricky balance between insisting on open source standards and perhaps enhanced functionality with proprietary formats. A workflow to allow multidirection translation between the various formats using some appropriate interlingua may be a solution, rather than worrying about a specific delivery format needed in a specific platform.

    • bat says:

      Is there a note of how to operate the Circus demo? How to move, how to reach the spaces like the rollercoaster I can see in the advertising images and mentioned in the installed assets?

  3. bat says:

    The space suit and helmet for visitors to the space-themed zones is VERY important 🙂 Immersion works great in space-themed virtual worlds, and if a team visiting sees a guy walking past with a baseball cap on backwards it sort of spoils thing. We have had some fantastic space themed experiences where the immersion was maintained so much that some team members running sort on oxygen in their suits have reported starting to feel breathless! E.g., see…

    If you are interested, I wrote an essay on space-themed games for educational use when I did an MSc in e-Learning in 2012…

    I plan to have a look at building and import of mesh models into Meshmoon when I get chance, and maybe to bring over the OpenVCE collaboration space build we had in OpenSim and that Tipodean converted for me to Unity… to try the Unity exporter.

    I am not really keen on lots of proprietary formats and, though I appreciate that realXtend and Moonmesh uses OGRE as a base, there seems to be a scene level that is unique to this platform.

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