I'm searching for OpenGL 3d engine which

1. will be easy-to-use and free
2. can be upgraded with some effects, graphics (e.g. add realistic water).

The needs are the following:

• visualize Earth with real height map (is it possible to use procedural generation or it is only used to generate random planet?)
• put some models on the Earth by (Latitude, Longitude, Altitude), like aircrafts, cars, tanks and move them according to some equations
• any other visuals like realistic water, atmosphere, trees would be excellent.

By easy-to-use I mean something like that (pseudocode):

Aircraft plane = new Aircraft("aircraft.3ds");
earth.loadElement(plane, new Location(lat,lon,alt), angles);

I understand that it won't be that simple, but maybe there are some simple engines.

And a few words about me. I'm using C# in my current projects. I know a little bit of C++ and I understand that most engines are written in C++. I've started learning OpenGL 4.3 with "OpenGL SuperBible". For now I'm looking to 3d engines like OGRE and OpenSceneGraph.

I would really appreciate any help.

You don't even need OpenGL skills nowadays.

I think it's the best if you would google the following engines / libraries and see if you like them:

• Unity
• Urho3D
• Ogre
• Irrlicht
• Horde3D
• UDK
• OpenSceneGraph

If you like a low-level feeling and maybe do manual OpenGL here and there, I advice OSG.

As a down-to-the metal guy myself, I can only advice you to not try to reinvent the wheel here. There are many pitfalls, a crazy amount of things to learn that has nothing to do with game development, and a truckload of issues related to porting your solution around to other platforms.

What is it exactly you want? Do you want to create games? If the answer is yes, see the post above. :)

If you like a low-level feeling and maybe do manual OpenGL here and there, I advice OSG.

Thanks for the list, I will take a look. And yes, maybe later I would like to do manual OpenGL.

What is it exactly you want? Do you want to create games?

Nope, I don't need game, I will try to explain. The main goal of our project is to develop and create architecture for modeling, something like HLA/DDS (this is not my part, so I'm not yet familiar with them). And to test/demonstrate it we need some visualization. An aircraft should fly, fire some rockets; some tanks should be on the surface and so on. In the beginning it can be done in very primitive way, just for us to see that everything is working (e.g. coordinates of the plane are calculated correctly and rockets are firing in right direction). But it would be great if later we will be able to improve graphics, add collisions, fancy effects and so on.

Nope, I don't need game, I will try to explain. The main goal of our project is to develop and create architecture for modeling, something like HLA/DDS (this is not my part, so I'm not yet familiar with them). And to test/demonstrate it we need some visualization. An aircraft should fly, fire some rockets; some tanks should be on the surface and so on. In the beginning it can be done in very primitive way, just for us to see that everything is working (e.g. coordinates of the plane are calculated correctly and rockets are firing in right direction). But it would be great if later we will be able to improve graphics, add collisions, fancy effects and so on.

That's basically the same thing. Except you may just want modelling software, combined with visualization software. You will need a game engine with integrated physics for the rockets part. Pick any of the game engines posted by ProtectedMode.

Trying to create all of the things you want with pure OpenGL is going to be a disaster for you. You'll have months of downtime while you learn the basics. Instead you could be working on the things you really want to do, which is: model things, put it in a scene, visualize it and add some physics interactions.

You can use Blender which is free modelling software, combined with any game engine for the realtime visualizations.