I need to make grid based levels with 3d models for a dungeon crawler ( as a recent example Legend of Grimrock), but i need to have several layers and place entities with properties and position, angle, etc. I was considering Tiled, using layers as height for each level, but it's very hard to work with and visualize. What can i use for this pourpose? The output format needs to be json, xml, or something i can use on my engine. Ideally i'd want something like Tiled with a 3d visualization/edit mode and support for loading models or at least some visual representation of them.