Map format for a 3D game

Question

I'm learning 3D programming and I decided to make a really simple "engine" where you can just fly around the map, etc. Only basic rendering of walls.

So, I was thinking - how can I save the level and how can I edit it. I don't want to make also an editor for it, because it is only a learning project, and not an actual game. So, I was looking towards this level format: UDMF http://zdoom.org/wiki/Universal_Doom_Map_Format although it is for a completely different type of game, still, it does what I need. Specifies vertices, floor, ceiling positions, etc. So, basic 2.5D geometry, which could be easily interpreted into a 3D space, which is more than enough for my purposes. There are also tons of editors (main reason).

BUT, I do realise that this is not really the best solution, and kind of workaround.

So, my question: Is there any "open" map format and "open" editors that I can use for my engine/game?

UPD: I'm working with C# and XNA, if that is important.

Answer 1

You could use XML (or something even simpler) that provides the location and other attributes of all the objects in the level. This would be the easiest solution (and have the benefit of containing whatever info you want but nothing else) but would not provide a level editor.

However, I know you want an editor (who wouldn't). Here is a very new, work-in-progress editor that looks interesting: 3D Scene Editor for XNA