Yes, that makes sense.

Now, I know it's hard and takes time and the advice is not do it and I understand why. But, is that written in stone? I mean, there is really no reason not to do a 3D game without an existing game engine? Is the knowledge present for everyone willing to learn or you need to be really smart?

Yes, obviously you need to be smart since you want to do everything alone. The knowledge is out there but you still need to interpret it correctly, implement it and let it function together. Engines, libraries, IDE and sdk's are simply tools to help you out with this, some more flexible then others. Off course you can create a game from scratch with a language like C++ but have you asked yourself "why do i want to do this?". You could also solder your own computer, use 8 big switches to insert the bits and bytes and start making your game from there.

The tools out there are to help you and speed up your workflow. There are no games being made anymore completely from scratch, AAA+ developers all use libraries and tweak there old engine here and there. So ask yourself why you want to build from scratch, put that reasoning in here and people here can break it down for you, maybe even pick a fitting engine for you.

The tools out there are to help you and speed up your workflow. There are no games being made anymore completely from scratch, AAA+ developers all use libraries and tweak there old engine here and there. So ask yourself why you want to build from scratch, put that reasoning in here and people here can break it down for you, maybe even pick a fitting engine for you.

I didn't said I want to build the game completely from scratch, but just without an existing/commercial engine. Many libraries can be used, like physics engine, rendering engine (Ogre3D) and so on.

Why would I want to build a game without an existing engine or using an open-source one instead of the commercial ones? Because of the control I'll get and because some of them are too expensive.

For example, the best one for me is Unigine Engine because it supports very big worlds because of its double-precision coordinate system. But I can't afford it.

Next one could be CryEngine SDK because of its beautiful outdoor scenes, but because of its authentication requirement I do not like it. From what I know there is no clear license for it also, so why can I trust that? I've saw too many valid complaints for it.

The third one could be UDK, but the one based on Unreal Engine 4 which is not here yet.

My last choice could be Unity, but I do not like it because is too generalized and they seems to focus more on what the community want, like mobile development for now. The Unity price is cheap, but you'll have to buy a lot of tools to be able to make what you want and that could become expensive. Tools like roads maker, interactive water and so on. In no time you'll get too dependent on other people. Yes, you could write the tools yourself, but how could you do that if you never got the advanced knowledge and experience?

If I would want to make many types of games and that I would want to make money from them I will use an existing commercial engine for sure. But, as I've said, my only goal is to create only one game and improve it as much as I can. So, if I'm planning to invest many years into this project, I want to be able to have as much control on it as I can.

The knowledge is out there but you still need to interpret it correctly, implement it and let it function together.

To be honest that's the answer I really wanted to get when I've started the topic, thanks.