Ok, thank you for your answers.

superman3272:
I know OpenGL isn't easy, i saw some basic examples (like boxes) and i didn't understood anything so I guess I should start with an engine based on top of it.
about the portability, is the choosen langage a problem ? i thought if libraries where multiplatform it would be enough. Am I wrong?

it's not like there's any Unity-style WYSIWYG engines for RTSs that I'm aware of.

I built a fully featured RTS prototype in pre-production using Unity and it took a little over a week, so I don't see why you would need something more specialized.

[quote name='GeneralQuery' timestamp='1348691767' post='4984100']
it's not like there's any Unity-style WYSIWYG engines for RTSs that I'm aware of.

I built a fully featured RTS prototype in pre-production using Unity and it took a little over a week, so I don't see why you would need something more specialized.
[/quote]
Then he's in luck. WYSIWYG engines are perfect for beginners, API-style engines... not so.

WYSIWYG engines are perfect for beginners, API-style engines... not so.

I'm wondering what the difference is as I've never heard these distinctions? I've worked with many different commercial engines professionally and they basically consist of a WYSIWYG level design tool (along with various other asset tools/conditioners) and then a scripting language (or some type of visual scripting tool like Kismet or C4 incorporates) and sometimes customizations in C++ either as a plugin or core to the build. The vast majority of games are built using a technology like this.

Mind you I'm not arguing or saying there isn't such a distinction, it's just that I've never heard of it.