* Make sure to have a look at the mapmaking part of the documentation. (Click "Documentation" in the main menu, scroll down to "3. Editor").
* Make sure you have a local server to test your map on. What you see in the editor is not always what you get in the game.
* Don't rely on undocumented behaviour, since that may change without notice.
* Some handy DM commands to use when testing maps are "/goto" and "/resetmap". See client commands for more DM commands.
* There are countless examples of different objects and techniques in the maps/dev/testmaps directory. Have a look at them if you are wondering how to use a specific feature.
* If you are stuck, ask around in #daimonin (see "Daimonin Chat" in the main menu)
* Please hang out in #daimonin and help others who are stuck :-)
* More tips here

Sometimes you want to have a door that allows a player to go through in one direction only without necessarily having a key. An example would be an exit from a dungeon that you don't want the player to be able to enter.

The following steps explain how to do this:

• Place your door, and lock it with a keystring, for example "my_locked_door"
• Set the door message to something meaningful, like "There appears to be no way to open the door from this side." This gives the player a clue that maybe if he gets to the other side, he might be able to open it.
• If you want to, change the default 5 second open time ("open counter") to something else. Personally, I think 5 seconds is too long, and usually change mine to 2.
• Put an inventory checker under the door. This is important to stop people who shouldn't be able to, to go through even if someone else has opened the door (you should do this for every locked door, of course).
• Change the layer field on the General tab to 0, and on the Flags tab check "inv. system object". Otherwise the player will be able to see the inventory checker.
• In the attributes for the inv checker, set "match key string" to "my_locked_door" (or whatever you chose), and check the boxes "match = slaying field" and "match = having" (this one is usually checked by default).
• For normal locked doors opened with a key, this is usually all you need to do. However, in this case you want to remove the marker (see next bit) from the player's inventory when he goes through, so check the box "remove match" as well.
• On the side from which you want to player to be able to open the door (only!), put a marker (on the Special tab of the Editor - this has the face "Info") on the floor a square or two inside where the player is bound to walk over it (if he could get to the door by not stepping on this square - for example in a wide corridor - it's OK to put down more than one, as long as they are all set the same).
• Set the marker's Special attributes: key string "my_locked_door" (whatever), mark duration 2. Don't change anything else. You don't normally want to set any marking message (you'll get a message from the server anyway when you go through the door).

And that's it.