It doesn't provide everything that those engines have but Urho3d is a very solid engine that has been under development for many years. https://urho3d.github.i

It doesn't provide everything that those engines have but Urho3d is a very solid engine that has been under development for many years. https://urho3d.github.io/ https://urho3d.github.io/ Someone else already mentioned Godot, which I think is fantastic and a lot of fun for making 2d games. I have not tried to use it for 3d, I understand its new renderer is making it more competitive with more advanced engines. edit: btw, I don't really agree with anything GP said. I just wanted to plug these two nice open source alternatives. I personally (as a casual hobbyist) did not really mesh with Unity or Unreal, for different reasons but I definitely understand what they offer to both beginners and serious businesses.