Zebbi , thanks- yeah, that's what I'd do. I'd use something like my Crocotile3d program to create the map and export it, then import into construct2 using q3d.
That's what I did with that example gif. I think I had to flip the y axis, or rotate the model to display correctly- q3d gives you options for sorting that stuff out.
I then used a tilemap object and physics objects with chipmunk plugin to handle collisions.
I'm not sure how I would handle collisions for a fps game though. It would be easy if you could use a 2d representation for collisions like wolfenstein, and use a tilemap object, etc..
It might be possible to create your own collisions by raytracing geometry if you want something more 3d.. or maybe try using the provided physics stuff in q3d( I havent tested them out ).. But you'd need a way to place that stuff efficiently, and change it easily if you need to.
I wrote an experimental feature in crocotile3d to export the collisions tile data based on a map I construct in it, and then I just load that into the tilemap object. That way I don't have to setup the collisions in Construct2.
It only works for side-view style maps though.
I don't know how well you are at writing your own code/etc. But you might be able to export some object point data from my Crocotile3d program and create your own instructions in Construct2 that takes that data and use it to create/place q3d physics objects for collisions. But I don't want to suggest doing that since I haven't tried it myself and have no experience with the q3d physics, so I don't know how difficult it would be or what sort of issues it may have.