One thing wrong with using a plane for making walls is the way the model would work in unity. In unity planes allow light to pass through objects and illuminate things that do not have any lights, so a dark corridor could be lit by lights far away around corners and in another room, it also adds light from all sources which can destroy any in game lighting effects you are trying to create.
Game engines are another world. I suspect they all have differences too. I guess you model the things in Blender first then adapt them to the needs of some game engine if you ever use them that way.
3D specifies that a face has only one visible side. This is the side where the ‘normal’ lives.
This is done for calculation purposes, (if you don’t see it, don’t render - calculate it).
That is why in a game engine, this back face side is invisible, they pass light, etc.
Blender has this option turned off by default. Blender does show the backside of a face.
This is done to help the 3D artist, navigate through the model. Having visible access from every angle. Otherwise, when back faces are invisible, you don’t see the model, confusing the artist.
My point was to make people aware of a possible limitation. I only use blender for game assets and starting with a plane can lead to problems in game lighting, just somerhing you may need to consider if making game assets. Unity does in fact pass light through both sides of a plane, from the ‘normal’ side it is attenuated.
Not to dig up an old thread, but I just got to this section. While it’s true that there’s a potential hazard with this and game engines, I think the potential problem is solved with adding a solidify modifier to the wall and applying it before export.
Without the modifier my plane was about 102 faces:
With the modifier it was still only about 230 faces:
Now that’s a pretty hacky solution, but if you wanted you could make this even more clean by just placing a cube and then do the lesson, modeling the one face that faces into the dungeon - that way the back is flat and not gaining the geometry at all from the front (~146 Faces, though I didn’t add chips):
Hope this helps future people in the lesson!