Last summer I wrote a 2D engine (and game) working off OpenGL. This summer I want to try something 3D.
I really liked the control writing my own engine gave me. I was free to stray from the beaten path and do things from dynamic lighting to user interface in unorthodox ways (for better or worse.)
I've used Unity3D before (years ago) and while it was fine then; looking back I can't stand the limitation it puts on your code/framework. You're forced to use their structure, their base classes like physics, lighting, particles (etc.) Not to mention that User Interface in Unity3D is (hopefully was) excruciatingly painful.
Anyway to get to the point I'm looking for a more minimalist 3D engine that has the bare minimum needed to get started with 3D with a lot of low level control. I'm looking for something more than a library but less than unity (only thing I have to compare.) I'm really hoping Unreal Engine 4 is in that direction, I was hoping I could get thoughts from someone who has worked with it, or from anyone else who might have thoughts on what I'm looking for.
EDIT: After doing my own research on the topic I'm leaning more and more towards just using OpenGL for 3D Rendering.