What is the best way to make Half - Life or DOOM style levels?

Hello. In my game I want to create levels similar to the ones in the original Half - Life / DOOM games but I’m not quite sure what would be the best approach to doing this.
I tried using various planes to create walls but that proved extremely inefficient and messy.

I have considered using blender to model the levels and room before hand and then exporting them into unity with unwrapped UV’s.
Would this work well? Does anyone know what would be the best way to go about doing this?

The original doom can be reproduced in 3D with box colliders for the walls and a capsule collider for the player and ennemies. (In my opinion)
I think the textures play for a lot and the models are all Low Poly.

I hope this helps a bit , Finally I think the Camera settings are the one you might want to play with (if you want visuals like those old games)

Well i’m trying to reach the same goal and for what i learn in the last month’s there is a couple of things you should know. First of all let me say that there is not a properly way to do so. And thats the tricky part of the metters becouse any of the “sugested” ways have their pro and con if that is the correct way to say it in english. Next i would give you a little idea of what you can do.

  1. Using an external 3D engine like maya or blender : The biggest problem you will find in this way of doing it. Is that you will have to be very carefull with the dimensions and size as well as the orientation. The only 3d model engine i have use so far is blender and is well known that have problems with orientation and dimensions. So this is the first problem you will encounter with external 3d aplication.
    The other problem is that if you have any trouble with the mesh or anything. You’ll have to jump into the 3d aplication and fix it from there, unless you have a mesh editor tool for unity like probuilder or so.

2)Using modular 3d environment : Well this was my second option when i found very frustrating with modeling entire levels in blender. But of course you will encounter another kind of problems here. The first one is that you will need to adjust the modules very precisely or you will have a lot of trouble making the nodes fit well. Another problem is that you will be limited in creativity to the number of modular pieces you have. So for example if you have only one corridor and two types of rooms is obiously that will be almost imposible to reproduce the variety of doom 2016 as a reference.

3)Using some unity’s 3d plugin: I have’t test them all for obius reasons the have to be bought and is not precisley cheap. I know that in the asset store you can find a variety of those. The only on i have use is probuilder so i will speak of that one. It is a very powerfull tool but also a complex one so forget about easy learning curve. But this dosen’t mean that is very hard to learn anyway. Lets talk about the pro’s.
With one of this tool’s you can relax about the dimensions and orientations becouse you work on unity editor itself. And is very easy to twick and fix mesh or uv problems.
But at least probuilder have not all the options you will spect or hope to have in such a tool. This means that you have not advanced mesh deformation like the ones you can find in external tools like blender or maya. So for example if you want to create a complex shape like a vaulted ceiling like in a cathedral you are going to have a bad time.

Finally my conclucion after trying every one of the mentioned building methods. I found that in order to reach my desired goal of making levels like doom but having a good visual impact like doom 2016. I have to find a proper balance between all of the three methods. Now i’m not working on environment in my project so this is freezed for now. But this is what i have in mind for building my environment.

Sorry for the bad english and the long answer. Hope you can get something usefull from all of this stuff.