True Room Over Room Mapping Guide
True Room Over Room is a feature new to EDuke32 that allows for the construction of sectors in a vertical arrangement. Other build games (Shadow Warrior, Blood)are able to fake ROR by having sectors in different parts of the map and rendering them on top of each other. The difference between that and TROR is that the sectors are physically on top of each other, making editing a lot easier and more automatic, while also making it easier to visualize what you're building.
TROR Editing Modes
There are two modes you should be aware of before starting to build with TROR.
Side view (orthographic view) mode
This mode allows you see a 3D representation of your map while in 2D mode. This is toggled with [F3]. It can be rotated with the [Q] and [W] buttons, and the angle of viewing can be changed by pressing [A] and [Z]. This mode is absolutely essential not only because it allows you to actually see what you're doing, but because in order to properly use TROR, you need to designate which is the 'active' layer that new sectors will connect to.
This can be done in 2 ways.
The first way is to press [ctrl-A] which will grey out all other layers except the one the viewpoint (the arrow in 2D/side view mode)is in, which is the active layer. You can move the view point up and down, allowing you to edit above and below layers, by either pressing [page up] and [page down] respectively, or more accurately by pressing down the [middle mouse button] and moving the mouse forward or backwards. This method is usually prefered as it gives you much more control over the vertical position of the viewpoint. If you find the greyed-out walls distracting, you can remove them altogether by pressing [ctrl-alt-A]
The second way allows for more precision as you can narrow the active editing range to the height of a single (or set of) sectors. Firstly, select the sector(s) that you want to be able to edit with [Right-Alt], and press [Ctrl-R]. It's as easy as that. Press [Ctrl-R] again to unlock the range again and be able to edit sectors normally.
Invisible surfaces viewing mode
This is for 3D mode when you want to toggle seeing invisible objects. All you have to do to toggle this mode is press [I], which primarily allows you to see objects you've made invisible with [Ctrl-I]. However, the reason why it's so useful here, is that it also shows you the boundaries between TROR layers (which are invisible in-game). This is a huge benefit when you want to visualize/figure out what's actually going on. It also allows you to edit the TROR surfaces and apply transparent or masked floors, and edit characteristics like the blocking and hitscan bits.
The following are a list of keys which are related to editing TROR. They can also be found in the mapster32 keyboard commands page
2D mode
E+CTRL sector extension prompt (sectors to extend must be highlighted)
E+CTRL make sandwich [needs better explanation]
E+CTRL punch loop through extension (loop points must be highlighted, e.g. with RSHIFT+LCTRL)
A+CTRL toggle auto-grayout of non-extended sectors
J+CTRL TROR-join sectors. The selection must consist of the two sets of sectors you wish to join.
U+CTRL Clear extension: delete the bunch (i.e. ceiling-floor connection) of the aimed-at sector's floor
PGUP/PGDN Change 'player' height in discrete steps in order to go through the different levels
TAB+CTRL Display one currently aimed at sector (of potentially many that lie under the mouse crosshair)
HOME and END as modifiers to AltGr: select all sectors whose floor's/ceiling's bunchnum equal the bunchnum of the aimed at sector (useful for further operations on whole bunches)
3D mode
I invisibility preview: toggle fake ROR texture on non-masked portals
LENTER+CTRL When aiming at an extended floor/ceiling, paste to all floors/ceilings of the bunch of the aimed at one
T, B and H work as with walls, though they set/toggle the bits only on one side