This question is for anyone who has used the c4 game engine. What are the pros and cons of C4 compared to Unity 3D? Please respond. Thanks. :?: :? :?:
What are you looking for in an engine?
Right now, you can do a bullet point comparison that is about as exciting as most of the generic answers that we can give you with such a vague question. However, if you give us some of the pieces that you are looking for, we can provide a much more balanced and useful bunch of information.
In engine vs engine topics, often the more generic the questions, the more useless the answers. If you ask us some specifics, we’ll be able to help you out better in a comparison. Otherwise you’ll get a bulletpoint comparison that you could have put together in a matter of minutes or the obligatory “use engine x because you’re asking on engine x’s forum!”
for c4 you have to be a c++ programmer, with unity you can use much easier programming languages. that’s the most important difference in my opinion. 
(it’s nice that c4 is quite cheap and that you get free updates forever.)
I used C4 at my college and I have to say, as an artist, Unity is leagues above C4 as far as ease of use. The C4 world editor is very primitive and is really only usable for placing your external models. I had the misfortune of building a whole platformer level using primitives in the world editor alone and it was painful.
There are some nice things like the built in motion blur, but the lack of soft shadows (stencil shadows ONLY?!) really kills it. The developer Eric is VERY VERY good about answering questions on the forums and the community is strong and willing to help, but it takes a serious programmer to work in that engine comfortably as everything is C++. I know some scripting and I can work with Unity but am completely useless when it comes to coding anything in C4.
If you’re hardcore about C++ and like that kind of thing, C4 is a great deal, with lifetime updates and a solid engine.
Oh, also the problem with C4 is their hardware requirements. It will not run on intel graphics, which kills a whole marketbase. Unity runs on pretty much anything 
C4 will not run on many things due to its OpenGL only rendering which is more than only a little problem on Windows unless you intend to target the hardcore gamers market only, simply because the majority update their drivers far to rarely
I think c4 already use directX for latest version. Their demo required June 2008 directX SDK or later.
really? would be cool
But the page does not mention anything on that on the features, only on the trial download
thought that does not remove the hardcore user requirement as it requires Shader Model 3 as minimum requirement (ATI X1300+, NVIDIA GF 6200+) unless you go that far that you even drop terrains.
Then you could get it to run (unsupported) on Shader Model 2 minimum
The new voxel terrains thought are a pretty nice features
maybe it uses directx for sound or input on windows but i don’t think direct3d gets used for rendering.
Incorrect. They use DirectX for sound, input or perhaps Xbox360 controller access, but not for rendering. Rendering in C4 is OpenGL (at least now).
I’m asking on their forum and I got this answer [quote]
C4 provides a rendering abstraction layer. Regardless of if you’re using DX, OGL, or anything else, you use the abstraction layer and it will handle the conversion to rendering API
[/quote]
What’s that mean?
that the implementation is Rendering API independent
But that does not mean that it itself has a DX renderer integrated, thought it means that it is simpler to integrate one if someone requires that than it would be if it was not designed like that.
The abstracted graphics layer is needed so C4 works on consoles and can be supported on the different platforms without too much of headache.
Unity internally works the same from what mentioned and so does TGEA GFX2 layer for example
Would there be any cheap alternatives to unity that work the same as unity?
Unity?
$200 is seriously undervalue for such a type of technology.
No. There are some free are relatively cheap systems you can use of course, but the amount of work required to get a functional game with them is exponentially more than with Unity. In short you get what you pay for.
Not that I am aware of. If you find any, I’m sure that everyone here, including the unity devs, would be very interested in knowing about it.
As a note, many people perceive C4 as being very hard to use as it requires C++ coding.
The engine framework is actually built so well, that using C4 on the coding side actually isn’t a whole lot harder than using C# here with Unity. Very clean API.
You have compilers to deal with of course, but that isn’t really a huge issue either.
As has been mentioned, the art tools are not mature yet for sure (cannot compare to Unity’s workflow), although C4 does have a full visual shader tree editor now, and voxel-based terrain modeling (doesn’t render using voxels). 
To anyone interested, try both, buy your favorite, or both. Each have their issues and benefits, so it’s up to you and your project.
-Jeremy