stumpled upon a pretty neat WIP by Matt Lucas
A short showcase by the Creator
A very long introduction/explanation by the Creator
Consider Donating to the Creator as so far this Editor presents really some essential features you would expect, i for one hope to see it grow.
Here the facts what you can do,
*block out evry room u can possibly imagine
*auto textue (you can change the res/texel density of the selected texture/material, you can define ceiling/wall/floor textures)
the final map can be imported into T3D/Unity/Ue4 - regarding the collision
in T3D you can use polysoup (as long as your map/level is not too complex but it might be better to create the collision seperately, a good starting point for the collision meshes would be the leftovers of the map building blocks.
What i mean with leftovers, when u build your map in blender, the block/mesh you used to build it, stays and by copying it you create new ares for the map, at the end you get 1 big mesh (this is your map) and plenty of seperate meshes (those are the building meshes u used to create the map).
I know it all sounds a bit odd but try it yourself and hf blending.