My question today is asking about which game engine I need to use for a game concept I've had. Below is the background, basic concept and a breakdown of what I need/don't need for this project to help you understand my needs. Please help me figure out the best path to choose for this project given my circumstances:
I have been playing games since an early age. The first game I modified was either Doom or Dark Forces, I cannot remember exactly which. Regardless, I've been tinkering with programming and worldbuilding for my entire life. I have a massive amount of experience with the Source engine and the Hammer editor. Before that I did some light programming in C++ for some personal tinkering mods that never went anywhere. Regardless, I went to school for architecture, finished, I have a job now and would like to again pick up the idea of game design/programming as a hobby.
I've had an idea for a game since the beginning of college and I've mulled it over constantly. Now that I'm to the point of being able to devote a portion of my time to developing that concept, I've come to the conclusion that I need a game engine from which to launch my concept.
The concept itself is a Non-Linear, First-Person-Shooter/Survival game. The most prohibitive part of the concept to reality is the need for very large game worlds, likely smaller maps with seamless transitions from one to another, much like that of games like the newer Elder Scrolls games or the Grand Theft Auto series. Other than that, I feel most any engine would cover the rest of needs of the concept.
Now to my abilities… I am very skilled in world design and creating textures and sounds. I lack in existing knowledge of programming; however, have many resources available to me by which I can adapt existing code to what I need. I also lack in the knowledge of model animation and creation; although, this too can be made up for with more training on my part. As I stated in the beginning, this project is a hobby, not my job; so I'm doing this to learn for myself, non-commercial.
Using the Game Engine Database as a format of parameters, I've broken down what elements I know I need and which of those I do not below:
Not looking for top of the line, but not basic style. Any API will do, d3d, opengl, etc…
Object Oriented Design
I would like to have cooperative multiplayer down the line, but not needed immediately
Sound & Video:
Physics is to include the ability of the player to manipulate objects in order to interact with the environment and for the AI to interact with the objects that the player has placed. Ragdolls would be nice but aren't necessary. Vehicles would be nice but also are not necessary. Also, weapons bullet trajectory is important due to the nature of the fps. I'm looking for a slightly less arcade-like bullet physics system.
The AI needs to be automatically path finding with the potential aid of nodes and minor decision making abilities. This needs further development.
Shadow mapping & projected planar, volumetric not needed.
Advanced texturing desired to allow for bump/mip mapping, alpha patterns and procedural textures.
I'm looking for a large/seamless world with buildings. The idea is a non-linear game requiring a great deal of unguided exploration of a large area. My experience thus far has been largely with the quake 2 and Source engines which have a rather limited level size. So I'm hoping to find guidance in the area of seamless/streaming level transitions in order to keep the level of detail high.
I'm looking for effects to the extent of Environment Mapping, Particle System, Sky, Water, Fire, Explosion, Decals, Fog, Weather effects and a Day/Night cycle.
Please help me choose the correct game engine for this concept. Feel free to ask questions and constructive criticism is greatly appreciated.