A floor is an object with the FL_FLOOR and FL_FIXED flags. Floor objects should be present in every room in the mud that should have a floor.

Set floor on a zone to the object id of the default floor for that zone. This'll then be tele-present in every room (FL_ROOM object) in the zone.

There's a specific "floor" attribute on room which can be used to override this. Set it to "-" to mean, no floor, or the id of the floor.

Saying a floor isn't there, and not having a floor specified are different. You won't be able to "put xxx on floor" if there is actually no floor there, for example.

If no floor is specified, it will assume template_floor_1 is meant for indoors locs and template_ground_1 for outdoors locations. It will assume no floor for outdoors nogravity locations.

You can have actual floor objects directly in the room. These override everything.

For floors which are hard and cannot be dug through, set "candig" to 0.

For floors which you don't stand on (for example, mud in wilderness swamps, which you stand in) you can use the onprep property of the object (in the mud's case, it was set to "in").