I'm curious to know the workflow when creating a game in Unity3D?
Does it generate a lot of code for you?
My understanding is that you describe the game in Unity and do scripting on the back end to do the logic. Kind of like you use Unity to describe the puppets and you use a scripting language as the puppet master.
Unity3D consists of a game engine plus a (fairly rudimentary) 3D editor. It provides meshes, textures, shaders, terrain, cameras, animations, particle systems, audio samples, and other kinds of object that are useful in video games. It includes PHYSX (a proprietary physics engine owned by Nvidia), and Mono (the open source implementation of the Common Language Runtime, aka .NET).
How much of this you use is up to you. You can represent all your data structures as Unity objects, build your world in Unity's editor, turn on the physics, and let events take their course, with a minimum of scripting. Alternatively, you could turn off the physics engine, construct your world algorithmically, and explicitly program all the behaviour and physics of the objects.
You can choose to program behaviour entirely in Mono (using one of the languages C#, JavaScript, or Boo), or you can write it in another language and link it with your Unity project. (The actual integration with the game objects must be via Mono, but this can be a fairly thin layer if you like.)
The workflow is much the same as with any game engine. Artists make models and textures and animations, audio specialists make the sounds, programmers write shaders and behaviour.
The community of Unity programmers is very helpful, both at answers.unity3d.com and forum.unity3d.com. (And maybe here at Stack Exchange?)
The best way to find out is to try it out: the basic version is free, and you get a 30-day trial period for the "Pro" version.
Unity3D is more of a wrapper/library than a 'drag and drop' game engine. It doesn't generate code nor does it come with 'off-the-shelf' scripts.
For example, Unreal has a default first person camera, character controller, collision detection and AI.
You have none of that in Unity3D. What you get from Unity3D is a game loop, component-based entity system, a comprehensive math library, means to load media, handling of meshes, camera, immediate mode GUI, shaders, rendering pipeline and other low level functionality. Plus a nice editor. You just have to worry about high level functionality. For example, you still have to code your own first person camera (if you are not using the default one). However, you do not need to deal with calculating the look-at vectors and such.
Unity3D doesn't generate any code for your game, strictly (It does generate code for running your game, to be more accurate, but none for your gameplay)
You will have to use the API to define your game. You can look at the examples that come with Unity3D and re-uses those code; there are a couple of pre-defined scripts, but usually you have to customize those to meet your needs.
You create the game through scripting; you write scripts for behaviours, design the level in Unity3D, and assign those behaviours to entities (or game-objects). It's very flexible, but it still requires effort to write a game. I would compare it to Flash for 3D.
The surface of Unity3D looks like it's super easy, and nearly everything is pre-build, but none of that is true. If you ignore to use already existing scripts (which exists for every engine, bad point against Unity) and plugins that you describe as somewhat ultra mighty, what they are definitely not, Unity is just an programming interface with editor.
You have most of the code by your own. I experienced that in 2 different projects.
The analogy with flash is quite right, but I don't really understand your analogy with puppets.
The good things about unity are:
The bad things:
The thing I don't like with Unity is that it feels like all the hard work is done, so programmers are much less valuable. On the other hand it's great for quickly teaching people how to build things fast.
So to conclude: Unity (or tool like Unity) is more for artists who can't reach out to great programmers, but can still know to do a little game scripting. OF COURSE you can make a full featured game, add realistic IA, doing a mmo net-code and what not, but big companies would not use Unity.
Programming models allows one to propose a solution that suits 3/4 of development tools so that it fits to those "independents" game makers. It values one particular tool and it also values artists, but not programmers (except the ones from the unity team, of course).
Unity is a good shortcut for non-programmers, but they have to understand that video games come from lines of code, and that you can't do everything just with an awesome tool. At some point it requires to know something about low-level programming.
Having a personal project in mind, I would not use Unity, because I don't like C# or Boo (Panda is good with python, so why bother with a commercial software ?), and because if I show my project and it's done with unity, it will be much less impressive.
Unity requires you to script, but without all the boilerplates. In a typical OpenGL game, you will need to initialize the matrices and cameras like crazy. In Unity, you create a script to tell the behavior of something, then attach it to an object to make it behave.
If by generate a lot of code for you , you would include pre-built functions that you can use to make your life easy regarding collision detection and rotation calculations (Library) then yes, it takes a lot of coding out of the picture and gives you optimized versions at hand and ready to go. Mostly functions that you will need specifically for Game Development in all builds.
It may sound redundant to say this , but in my experience , when Unity3D isn't busy crashing or building it's making my life easy by letting me change whatever I want and leave the Quaternion based math to the people that have a master degree in mathematics and still trust me enough to le me change whatever I want.
It will write nothing for you, rather help you out in the way it thinks is best and let you write whatever you want.
In one word, Flexible
