From the wireframes it looks very interesting. They must have a good scene-management. It really displays only visible contents.

Sorcerer, you should produce one of your wonderful tutorial videos for the s2 engine. I will host it, if you do!

Maybe a little later. I just found a serious bug on one of their editor. Whenever I try to add waypoints for the Ai, when them I try to save, the editor will crash and delete my scene file.

I really dont understand that. The most important point for a sophisticated software like a 3d engine is the quality of their documentations and examples. That is one of the reasons why Unreal-technology sells so well.

And I also dont understand it from the other way around: If you spend several years to produce such a great tool then writing a manual is just a small task but it helps all the world to dive into your genious masterpiece of software so it could even feel good for a developer to write such a documentation. It can be fun and can show the world your concepts and ideas.

But when they lack good tutorials then they do not sell enough copies and they wonder what is wrong with their great tools and abandon to improve it later on.

Documentation is just another part of this software and should meet the same level of support.

Well, I finally manage to talk with the other S2 developer. And the problem is always communication everywhere, isn't?!
The guy is implementing a GLSL "interface" for the basic version of S2. He even showed me a screenshot of a postscreen effect. It does look very nice!!
We also talked about the lack on the scripting tutorials and examples on the manual. He said that he will take care of that.

So, I guess I will be making a new video tutorial very soon.

You can try COLLADA , a team centric almost P2P type system for team work.
Post, upload, download are basic foundations of the App and it has a few more interesting features and is presently FREE.

@ Friendly_Frank absolutly agree with you about documentation and in particular, tutorials.

Adobe, Discreet, Macromedia etc all understood this and are still selling strong from their initial documentation releases, they were visionaries who hired educators to write the content as far as I know and of course, all are now standard names for the industry.

Why other vendors do not pursue this course is crimnal when you look at some of the mighty software that vaporises due to lack of documentation and therefore, user familiarity.

Yes, Collada is a fine alternative format very similar to FBX.

If you ask me then I would like to have much wider support for Collada. FBX is becoming an Autodesk format more and more. All the support for XSI, Lightwave and so on is gone. Currently Autodesk only offers FBX for Maya and Max. So I am not sure what happens to this file format in the future.

Collada is free from that. It should become the real alternative for engines and modelling applications. But unfortunately not every software supports it currently. I did not find a plugin for Lightwave as an example.

Here are some more details about Collada.
software that supports collada:
https://collada.org/mediawiki/index.php/List_of_products_that_support_COLLADA

The COLLADA 1.4.x feature set includes:

• Mesh Geometry
  
• Transform hierarchy (rotation, translation, shear, scale, matrix)
  
• Effects
  
• Shaders (Cg, GLSL, GLES)
  
• Materials
  
• Textures
  
• Lights
  
• Cameras
  
• Skinning
  
• Animation
  
• Physics (rigid bodies, constraints, rag dolls, collision, volumes)
  
• Instancing
  
• Techniques
  
• Multirepresentations
  
• Assets
  
• User data
  

As you can see one could save complete levels, animations or even cut-scenes in Collada-format.