Terathon Software LLC
May 05, 2005
Windows, Linux, Mac OS X, PS3, Other
Languages Written In:
The C4 Engine is a comprehensive suite of robustly implemented game programming tools for the Windows, Mac OS X, Linux, PS4, and PS3 platforms.
|License Name||Price in $US||Source Code Included?|
|Subscription Edition, source included, updates for one year|
|Standard Edition, source included, updates forever|
|Professional Edition, source included, updates forever|
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I've only been working with the C4 Engine for a while now, but I've had enough experience with other game engines, to tell you what things made C4 the obvious choice for me.
Integrity - Refreshing to see an engine tell it straight about needing source code access. Anyone saying different is telling half truths. Period.
Cost - Reasonable price, forever, no upgrade costs, no royalties to further constrain your budget! Depending on your license type you can even have small features added or problems solved for your own needs. For simple problems Eric or the community will normally help over the forums.
Support - Eric is terrific, I can't say this enough, timely responses to questions/problems, new features and bug fixes regularly worked on. A professional and mature community offers its support as well.
Architecture - The design, and the clean thoughtful approach taken to implementing all its features makes understanding and working with it an enjoyable experience.
Features - Regularly being updated, the roadmap shows the few features missing that contenders offer (SSAO, HDR) are being implemented, plus it offers a some things you will only find in C4 like Transvoxel Terrain, Horizon Mapping for example. Being able to request small feature additions, and have a part in discussing with the community and Eric himself the importance and implementation of features shouldn't be under-stated.
Performance - After some stress testing, I'm extremely impressed how far I can push it. It's well designed to let me push the envelope in an organized way.
Modular - Full source and a clean design lets me choose my priorities and extend as needed.
Plugins - Being able to add plug in new features as opposed to replacing parts of the engine allows you keep your game updated to the latest version of the engine without needing to manually merge them.
Extremely happy with my choice of the C4 Engine. If you serious about making a game, take a serious look at C4, you'll be happy you did!
Updated Review- Updated on 5-30-07 to reflect users increased experience and updated features-
Review from a graphic artist's standpoint.
-Mapping types-C4 supports parallax, normal, gloss, emission, and cube mapping, there may be some i am forgetting, but only because c4 supports so many! The implementation of these mapping types are also very well done, the engine even includes a tool to generate a normal or parallax map from a gray-scale map when importing it.
-shaders- C4 supports various shaders from reflection to refraction and ones from the above mentioned mapping types. Most importantly, they run fast!
-Terrain- Terrain in C4 is fairly lacking, i hate to say it, however future plans are to redo the terrain system and even add in a foilage system similar to those used by packages like speed tree (billboading lod vegetation...etc). Because this feature is being worked on now i will not let it affect my rating but i do feel it should be mentioned for those wanting to buy the engine before that particular update.
-Misc Features- C4 supports many types of misc things such as fluid and cloth sim, and very good geometry occluding. C4 uses a zone (portal) rendering system that will not only cull back faced tris but will also allow the engine to seperate your game levels into chunks and therefore allow you to more optimally use the max tri count your target hardware can support for each given area. This feature not only removes whole sections for rendering that are out of sight but it goes down to the individual object level.
Ease of Use-The engine is very very easy to use, especially as an artist.
-Editor-The engine has a built in editor that now allows full lighting and shaders to be seen within the perspective viewport. This is an excellent way to more precisely fine tune the lightign and shaders without havign to go back and forth between gameplay and the editor, along with this it gives a fairly similar fps rating to what you will experience ingame when previewing the full lighting, so its great to test performance while in the editor too!
In the material editor you can very easily put together soem very realistic materials, just throw in your textures into the appropriate slots, adjust specular/microfacet shading (if being used) and there you go! The material manager allows lots of things to be tweaked for each given material too, including color for many of the effects for either fine tuning them or adding some effect.
Then you also have the node options menu, to change a lot of the settings for each object in your world, simply click on it and go to the top menu into node options. Here you can tell objects to use certain shaders, allow or not allow certain shadows, apply scripts (there is also a visual scripting system built into the editor), and many many other things.
Stability and Performance- The engine's performance is rock solid for the features it supports. One thing some still don't understand is that C4 is purely a shader engine, or as some would say "next-gen" (current-gen). So please don't expect the engien to run on a low-end card all that well. Think to yourself, "would i be able to run Doom3 at full graphics with my card...?" if the answer is no then please don't expect the same from C4, that would not be logical. Pick the engine that is suitable for your needs. However if you need a kickass graphical engine for a great price C4 is here. To go a bit further into performance it is worth a bit of a mention that a lot of optimization techiques to speedup rendering have been implemented into C4. Namely a lot of optimizations with the lightign and shadowing have been done, although it is up the the user to activate these options intelligently, when used right it can help improve overal fps (though appropriate level design for such an engien is the best place to start for performance improvements).
I am giving C4 a 4/5 in this category only because i have experience a few crashes when trying to get some work done late at night. However these are rarely encountered and when they are it is a result of a bug, which is reported and fixed by eric asap.
Support- Hands down C4 has the best support i have ever seen for any engine. The owner himself, Eric, usually gives support directly through the forums. He does this so much it has even led me to develop some conspiracy theories on this subject on just how does eric does it ;-)
Curve-You also have to give the engine a rating curve because of its price. For $200 you get all of the above and the source code, what more could a person wish for?!
Basically i am trying to say, if C4 fits your needs, buy it!
Jarrod M. Christman
so far my experiences with this engine are purely on the graphic artist side and i only have one thing to say.... wow! this engien for its price offers lighting as good as doom 3, nice mapping techniques like parallax, gloss (controled specular), emission maps...etc. it supports about any kind of shadow you could possibly want with very little performance hit from using them! on top of that it support seamless indoor/outdoor tranisitons, is very good with handling rendering, has built-in editor and so much more!
and you can get it all for $100! very good price i must say. atm since the engine isn't finished (needs better terrain and more editor features) it doesn't have everything but its all being added at a very fast pace and the developers of the engine seem to be very dedicated. no use in waiting to buy, i would recommend this engine. even though this engine has features that are lacking or not there at all i'm giving it a 5 on features because it does have a lot fo features that you will not find on any other engine on this site for the price of a $100.
Jarrod M. Christman
My second engine. Leary from the experience of the first, I actually tried the demos and asked questions.
Very helpful and tolerant community. Everything worked as advertised. My assets all worked with some tweaking. COLLADA rocks ... no dts hoop-jumping. I bought the engine. I recompiled the engine no problems a couple hours later and got right to work. The code is so neat and well organized ... my god ... I hate to mess it up.
This is an outstanding engine. Well written, a programmers delight, impressive feature set and an encouraging list of planned future features. Jump on the forums and you will discover an intelligent community who seem quite intent on helping each other out, without any of the nonsense found in other game development communities. To summarize, the $200 I spent on licensing this engine was money very well spent. No regrets whatsoever, I encourage other serious game developers to do the same.
Hello all, I have searched for 2 years to find the right 3D game engine. Although there are some areas that C4 has yet touched, as a license holder I feel the engine has more potential than all others which I have looked at. Additionally, C4 has an indy price you absolutely can not go wrong with. The professional license is well worth it for a company to invest in. The engine's programmer has a vast knowledge of 3D programming and the platforms the engine runs on. One of the most attractive things to me about the engine is that the author responds directly to questions and comments (and in a timely manor).
I give C4 my highest review of all the engines I have looked at.
I've been searching for months a good game engine that feets my needs and C4 Engine is perfect for everyone (from indies to professionals) and that price is nothing comparable with the capabilities of the engine. It has excellent features that you can find only in expensive engines, the code couldn't be more clean and detailed, it has a powerful built-in editor, it is constantly being updated(blend animation and physics engine soon:D), eric is always there for support and the community is great . If you're good you can make very powerful games with it of any kind. Torque,Beyond Virtual, or TV3D CAN'T be comparable to C4 Engine. The best!
I got c4 right before the end of $100 and it was the best investment I could ever make. Even at it's new price of $200 it is the best engine, for coders and non-coders. Why is it $200? Because of it's new found popularity and features, that make selling it for $100 "giving it away". But even with $200 (witch is more like a donation) it will be sure not to stay their. With collida import and unreal type rendering, it is the best engine around if you are willing to wait and or impliment some of the features yourself.A would editor make-over will be done in the next build. The more features the higher the price.
It has a very very clean higharchy for C++ coding, nothing like the "porque engine". Fetures are not broken.
Anyway you get direct support from the guy who made the engine. And don't worry about lightmaps, shadowmaps and bsp build-times. Cause you can instintly play your game :).
Features: Top notch, features you know from commercial features like soft shadows, realtime rendered portals, parallax mapping and the lot. There are also a lot of tools build into the engine like world editor, visual script editor etc. MacOS Support is another feature that is important to mention! 5 Stars
Ease of use: Really, the only thing that COULD be a little difficult is the C++ useage IF you don't know C++. But the sourcecode is well documented and tue to the compiled binaries you don't need to look at the sourcecode if you don't want to. There are good tutorials, the API is well documented and the wiki will help you a lot. 4 Stars for the inexperienced programmer but actually 5 stars if you know C++
Stability: There are a few bugs but since Terathon has a good bug tracking system and the engine runs pretty stable this is a 5! 5 Stars
Performance: Depending on the features you use, the performance is always very good. Can you expect to have all the eye candy with a FX5200? Of course not! But with all on the max. and a resolution at 1280x800 it runs pretty good at my laptop (1.8 GHz Core Duo, 1 GB RAM and a Radeon X1600). Not perfect but acceptable (with max. features!!!!). 5 Stars
Support: Eric is always there, he is a fast responding, high intelligent programmer. Does he get any sleep at all? I don't know. All I know is that I'm receiving the best support I've ever got. I came across many languages and engines (Blitz3D - support bad, PureBasic - support good, Dark Basic - bad, Beyond Virtual - ok, Torque Game Builder - ok, 3D Game Stuido - bad) but C4 beats them all.
One note: I got this engine for $100 (old price) but even at $200 with yearly upgrade fee of $75 this engine underpriced! Featurewise it's playing in the same league as the "big boys" and there will even be a PS3 port! Go get this engine, will you!
C4 is the most well laid out engine I have ever used. All of the features work seamlessly together. The Engine is still in a development stage and large features still have yet to be implemented but by the quality of the already installed features, I know the finished prodect is going to be nothing short of Phenomenal.
The graphics are astounding for a engine that can be purchased for $100. The lighting, shadows and texture effects such as normal mapping and reflections are all top notch.
I highly recommend C4 for anyone looking for an engine on a low budget but is looking to make a game that looks like it was made on a big budget.
The level editor included with the engine is very easy to use, for someone like me that is used to using the UnrealEd and MaxEd, I find C4's map editor to be extemely easy and quick.
Soon to be implemented are the terrain, foliage, physics and many more lighting and effects that will only make this engine that much better.
Without a doubt the C4 Engine is the most versatile and useful programming tool I have ever used for designing a 3D game. C++ is the language of choice for game design. Many game engines are messy and understanding the code is a nightmare. With C4 it's all incredibly clean and well structured. You can actually learn good coding practice by delving into it. If you want a clear approach that won't leave you doubting your decision with support that is unsurpassed you have come to the right place.
I've learned more about 3D game development here than anywhere else and am totally satisfied.
Note: I type this as a creative type, not a programmer, and so my review is mainly on the editing tools, and not the code. Others are better qualified to speak on that aspect.
C4 is an engine I've come back to a few times now, but have left out of frustration. Though powerful, I really believe the editing tools could use a complete redesign, not so much in terms of layout (the editor is actually very nicely setup), but more in workflow, and in documentation.
The workflow is rather unintuitive in my experience. In most engines I've tried, I can - with little to no research or reference to documentation - get a terrain setup, get assets imported and placed, and basically have something "playable" in a short time. Sometimes as little as 20 minutes.
C4's workflow, however, has stumped me on every attempt. It's very unintuitive, and things just don't seem to work as you'd expect them to. Eric, the creator, seems to leave a lot of the tedium to the designer/creator, rather than handling it in the background, which rather exacerbates it.
An example is terrain. Now, being voxel-based, of course the terrain editing is going to be a bit different from standard height-map editing. However, it really shouldn't be any different, from a designer's stand-point, than editing a regular heightmap. It should be no different - to the artist - than sculpting in a program like Mudbox, or even in Blender's Sculpt mode. Again, that's if the workflow were setup to be intuitive, which is where C4 falls short.
Creating a terrain is a multi-step process that is not at all intuitive, and is incompletely documented (which I'll explain momentarily). Setting up textures for the terrain is also highly cumbersome since, as I stated before, Eric passes a lot of unnecessary tedium on to the designer. Specifically, there's a process of setting up what's called a "terrain palette", which is basically a way of mapping what texture is painted on to what surface (top, bottom, left, right, front and back) for use in voxel painting.
Now, were the process as intuitive as I'd expect it to be - and certainly as it is in other engines - where you assign the various textures (diffuse, spec, normal, etc) and then the engine handles the rest, it'd be 1, 2, 3 easy. But it's not. You have to create the texture palette and then - and this is where the incomplete documentation comes in - create a shader to make the terrain palette usable on the terrain itself.
My problems with this approach are 2-fold:
1. There are other engines that allow you to fine-tune and tweak specific settings for each of your textures and their influence on the material. The Esenthel engine is probably the best example I can think of in terms of creating and editing materials. It would seem to me that if the "bare bones" of a usable terrain palette requires a basic shader setup, that this should be created automatically when the terrain palette is created. If a person wants to go in and tweak it further, then fine. They can.
But if someone simply wants to plug in textures and go... well, not so much, because the tedium of creating that basic shader is passed on to the user. In my opinion, in the interest of usability and intuitiveness, it should be handled automatically.
When this was mentioned in the forums, Eric has gotten rather defensive and explained it away as "because it's voxel terrain, not a heightmap". That's nonsense to me.
2. The documentation in their Wiki - as of my typing this - does not reflect the need of a shader. It walks you up to the point of selecting the materials, but says nothing of having to create that shader network, nor provides the instructions to do it. It's been like this for many months now, despite having been discussed in the forums.
All that said, I am giving it another go and have ordered the "Beginner's" book for it, which apparently does a better job of explaining the engine than the Wiki does.
I know the engine is powerful, and can yield some beautiful results, running smoothly at the same time. If they could get the usability and intuitiveness of working with the editors and its asset workflows to the same level of polish, I'd easily give this engine a 5 out of 5.
C4 is a really great product.
Having evaluated over a dozen Engines, C4 is the one I bought after giving its Demo Version a longer Try.
- Support: The Level of Support you get from the Developer and the Community is outstanding. Never before i've received so much support and every Problem i had got resolved mostly within an hour.
- Toolset: The Editors of C4 allow a nice workflow which is in my Opinion very important because as an artist you don't want to spend days or weeks getting good Results. The Shader Editor is designed for easy use and despite its simple nature is extremely powerful. If a Shader Node is needed that is not implemented, it will often be implemented and ready to use in the next update. The World Editor is also easy to use, but it needs a few tweaks to become even better. The Script Editor allows a lot of Interactivity inside the Game World and is easy to use and powerful.
- Rendering: The Quality of the Visuals is outstanding. But as with most engines, this depends on what you are capable as an artist. I'm still a beginner considering what I can do as an artist, but the Result I got is really nice. Performance is also excellent, but for bigger Levels you should really optimise its layout and use the Engines Optimizations
- Sourcecode: You get full Access to the Engines Source Code, and being a Programmer myself, the Code is extremely clean and easy to understand. It is pure fun just to look at it.
- Stability: C4 is rock-stable. It only crashed once because a plugin didn't support the newest version of the Engine.
- Portal System is powerful but difficult to use at the moment. However, it will be updated in a future update
- A built-in Particle Editor would be really cool. There is one from a User but i'm to stupid to include it inside the Engine
Also, the Price of C4 is really fair considering what you get from it. It is affordable for nearly everyone and delivers quality that is normally expected at higher Price Ranges.
The next few weeks will be really exciting, because C4 is getting a huge update which will bring tons of new features like a LOD-System for Voxel Terrain and a Physics Engine which allows more interactivity inside the Game Worlds.
The reasons that convinced me to use C4 over any of the other engines available .
Technologically top notch product.
Eric Lengyel, the main programmer is an experienced industry professional.
The community is very supportive and tolerant,eric himself is very active in the forums.
budget-friendly indy license
full source code
The C4 engine is a professional and fast game engine that offers features expected in engines many more times expensive. For the cost of the license it offers full source code for the engine and all tools as well as superb support from the author and community. Extending the engine is very easy and despite having the engine source code no modifications are necessary to get game specific functionality within the game world.
The art pipeline and approach to world editing, whilst nuanced, is very powerful and only requires a license purchase for developers that require the source code, making it attractive for small teams with limited resources to get started without requiring a large number of engine licenses.
The engine is implemented in C++ with a clean scenegraph architecture and whilst it requires developers to be competent in C++ to make the most of the engine, tutorials and assistance available through the community make it easy to get started developing with the engine. Performance is generally quite good on both supported operating systems but requires adequate hardware to run the supplied demo.
Features: there are a lot of great tools and what not that come with the engine. They are not as nice as some others and but I believe this is being worked on and as long as they work that's what really counts.
Ease of Use: The code is extremely easy to follow if you have a programming background. Ive used many of the top 10 engines on devmaster and I would say this is the easiest one to use for serious development.
Stability: Eric does not release something that does not work. This is not an issue. I was shockingly surprised at how bug free, how stable, and how fast the engine runs. I have yet to run into programming short cuts that end up leading to bad spaghetti code.
Support: I have yet had a question go unanswered and most the time very quickly in the forums. Eric is always on there helping people. The people of the forums are also very active and don't mind helping everyone from the newly started developers to the seasoned individual.
I really do enjoy using this engine and really cannot wait until 2.0 comes out. The license cost of the engine is out of this world for the type of product you get.
I was Torque Customer for 4 years,after they more into 'Professional' market,i look around for alternative engine,i have reviewing also Unity3d,once want to buy for professional,but because lack of new Engine runtime update(they use Mono 1.2.5 right now),the mono runtime already on 2.x,which offer more stability,command set.So i stumbled across C4 Engine which to be honest a very friendly community,smart,and the support(Eric) just excellent very technical know how about what he is writing on,even Eric himself working along with ATI dev to fix up some problem on ATI's driver,this is really shown up Eric's capabilities as good developer. The one i embrace on C4 is not just the community,but also the flexibility,you can pick between built-in(v2.0) physic engine,physic by nvidia,bullet,or any other physic engine that you want to integrated,not to mention the voxel terrain(2.0) :),and iam the one of lucky one who gets lifetimes update because i bought before v2.0,Macos Support,what could be more good than this? well maybe web based player :D,or opengl 3.2 upgrade and tessalation support?
I can't say much about how well structured and commented the code of C4 is.
I also can't say much about how easy it is to implement own features and plugins for C4.
I also can't say much about how good the learning curve for C4's coding structure is.
Because being not a programmer but an artist I can't say anything about these things.
But that's what my programmer and many other programmers say, who work with this engine.
What I can say is that I am very happy about how easy it is to get good looking and working results with this engine even without knowing anything about C++.
Texturing for this engine is a real pleasure because of the high quality maps produced by the generators working behind the texture importer. With C4 I am able to generate normalmaps, parallaxmaps, horizonmaps and even ambient-occlusion-maps from one single heightmap. Combined with the powerfull graphical shader editor users without any knowledge of writing shaders are able to produce materials and shaders that are easily able to hold a candle to the big engines out there.
That also applies to the graphical script editor which allows level designers and artists to create scripts in their world without learning a scripting language. A great assistance for people like me.
When I was searching for an engine that could fit my needs I was looking for something that could handle large terrains in a high quality. At the point I purchased C4 the engine couldn't handle the terrains I needed for my project. I talked to Eric, the programmer of the engine. He told me that he will implement those features. Because of the professionalism Eric, his engine and the community left to me I purchased a license and hoped that the upcomming terrain features will rock as the rest of the engine.
But the terrain features weren't as good as I expected them to be.
C4's terrain features are way better than what I expected and broadened my mind about creating terrains for Computer games. At last it is possible to create high end terrains with real overhangs, rocks, bridges, caves, cliffs and tunnels because of C4's voxel terrain. With the upcoming LOD system and background terrain loading features the level designer knows no bounds anymore in terrain creating.
Not a feature but also very important is the support. Eric is almost always at the forums and questions and problems with the engine get answered very quick and competent. I couldn't wish a better support.
If I would mention every feature I like on the C4-Engine the list would become very long.
So I only have to say that with every build of this Engine my enthusiasm for this engine and the joy working with it are growing even more.
Keep up the good work!
First,Before buying C4 license I've tried many free and commercial engines out there. I also worked on few projects using other game engines. About 2 years ago I've downloaded C4 demo and was impressed by feature set and World Editor capabilities.
I've showed it to few artist friends of mine and they were working in WE in 30 mins or so and were as much exited as me. Before buying I've asked few question on forums and (from my previous experiences) was hoping to get answers in couple of days, BUT I got all answers in 30 min !
I decided go and buy license (200$ when I bought it). Reading license term I was pleased VERY much about lifetime upgrades !
Another surprise waited me aftr downloading sources and opening project. Clear and self explained code. Many features were implemented the way I thought they should work.
Did I mentioned strong community and INSTANT support on forums ?
After getting access to C4 forum's licensed only sections I find many useful community made tools and addons (like Physx, bullet integration, Effects addon etc. )
All bug were address in rocket speed as well.
Year later after purchase I've got voxel terrain feature and more to come !
Very soon we'll got 2.0 release and tons of new features and integrated physics as well (one can continue using third party physics engines if preferred )
C4 is best investment I've made and new updates and exciting features remind this pretty often !
Still not exited ?
Simply take look at feature list that will 2.0 bring:
As being both a Torque and Unity user before, I will say this engine is the real pass that enables me to the game world.
Stable, productive performance, and professional community support, it shortens the time and helps wield the serious weapons necessarily to get the work done.
First, sorry for my bad English, it is not my native language.
I have been looking for C++ based game engine for about half of a year and evaluated all engines in price range under 1000$.
I have chosen C4, because I found it as the best choice for C++ programmers in this price range. I like the way Terathon puts the clarity of code structure on the first place, even sometime sacrificing backward compatibility with previous versions. So no there is no redundant code in it. Feature set is complete enough for my project (after the foliage is implemented) and all I need to make a game is within the engine (and now the physics too), so no external libraries are needed, thus making the portability a breeze.
Having the engine source code at your hands is the greatest advantage of C4, that makes learning the engine and debugging your applications easier.
The only thing I didn`t like in C4 is a World Editor for being somewhat clunky and uncomfortable for my artists. But I hope it will be overhauled in upcoming 2.x release (as Terathon promised).
Support is just superb.
While not a "professional" programmer by trade I was able to follow simple instructions and actually compile C4 without a single warning!
I am using C4 as time permits as a learning tool for C++ and am having a great time with clear visable results.
Erik has put a lot of thought and effort into this engine and I have the upmost respect for him (and high expectations for the upcomming release!)
Bottom line - I love the stability of the C4 engine and how well designed it is and hope you will too.
After having developed and released a few indie games I was looking for a game engine that would fit my needs. I came across the C4 engine and after some research I could tell it's a very capable high end engine. I have been using it for a bit more than a year and it's proven to be very stable and pretty easy to use.
The included demo examples suffer from developer art but don't let that fool you. Even tho the examples may not have the best eye candy, if you are a developer you can tell C4 is an advanced engine with advanced features.
Perhaps the best part about C4 is that it comes with source code. The source code is clean and very well architected. The deeper parts of the engine you don't really need to dig into and the top layer is relatively easy to follow and figure out. The demo source is also very helpful in showing how you can do things and get started on your own game.
The built-in world editor still needs work in some areas to make the workflow more smooth but a lot of it is details that could be improved like selecting and manipulating things in your game level.
C4 supports voxel terrain and this is great if you need big areas of outdoor terrain. The terrain sculpting and texturing tools are still a bit limited but improvements are under way.
The graphical shader editor is simply awesome. Being able to build a shader by combining various function blocks is much much easier and faster and more intuitive than writing a glsl shader or vertex and fragment programs. And the way the shader/rendering system is designed, you don't have to worry about shader explosion where you need to write a number of different versions of a shader for different circumstances.
The graphical scripting editor is fine for simple things like setting up triggers and what not but not really suitable for more extensive game logic. IMO it would be nice to have a real scripting language in C4 also.
There are still features missing in C4. Some of them like native physics and terrain LOD is coming in 2.0. Other features I'd like to see are a complete foliage system, HDR rendering, realistic water and full support for shadow maps. When C4 has these features it will be a full featured game engine.
Last but not least, the support on the C4 forum is great. Ask a question and you are likely to have some answers in a short while.
EDIT: It seems something went wrong, my review is on the page twice but I can't edit or remove the other one.
In my opinion (as a learning programmer) C4 engine's best point is its readability.
Unlike torque, for example, the code is organized and structured (thanks to the node/controller based system).
Add to that really good support service (Your questions get answered really fast) and you get a great package to learn from.
Ofcourse its readabilty and great support are not the only things that are good about C4. It has all the graphical bells and whistles you'll ever want, voxel based terrain and a good editor to use it with.
The package does not have any "bad" points persé, it is however an engine for programmers and an understanding of C++ and your basic maths are required.
Also the engine has no advanced physics support at the moment but the next version will fix this (and bring with alot of other new features).
This engine has been incredible to work with so far.
Community for C4 is responsive, and helpful.
The internal structure of this engine is incredibly clean, and the learning curve overall is not a steep one.
Features are continually added on an already feature rich engine.
So far the engine has not crashed, and hasn't had any performance problems rendering on my Macbook.
Biggest Highlights in my opinion.
Runs on both Windows and Macintosh systems.
I honestly wish I would have learned about this engine a year and a half ago and saved my self some time trying to deal with other solutions to indie game development.
I have been the proud owner of the C4 engine for about a month now and none of my high expectations have been let down. Purchasing this engine has been one of the best choices that I have made lately.
In the past I have tried many trial edition engines and I have even purchased other well known indie engines but have always been disappointed by the quality and or lack of support.
So why is C4 so impressive to me? First of all the excellent support that can be found on the forums. The forum is constantly be monitored by the engine creator Eric. He manages to answer nearly every question out there regardless of how simple or complex it is and all of the members are very willing to offer support as well. I have learned a great wealth of knowledge simply by reading all of the different post out there and questions asked by other people.
Another excellent reason to consider this engine is the fact that you get the source code. I have noticed that this is something that is not offered by many of the other engines out there.
Another excellent feature is the examples that come with the engine. These also include the source code which are clearly written and include a lot of comments. I am still learning Cpp and this engine has made it so much easier to understand how to get things such as characters, bugs, or even a simple ball onto the screen and get it moving. To me learning Cpp is much more easier and funner when you get to learn it with a game engine instead of the old command prompt.
Once again I was also amazed by all of the different 3D packages that you could use to make models for your came. This engine uses the collada format which is supported by a large number of art packages.
To sum it all up if you want a quality engine that is very stable and can produce amazing graphics then take a look at C4. Browse around the forums and C4 and simply see for your self. You will be amazed like I was and still am.