Making a multi-activation linedef


Multi-activation linedefs are linedefs that can activate different things each time they are crossed, so you can have a door that will only open the third time you pass near it, for example.


The method as explained step by step in Bug's Revolutionary Techniques for Doom and Doom II v2.3 guide:


  • Trace a linedef which has the function lower sector with tag XXX to the lowest near.
  • Create 2N - 1 adjacent sectors, where N is the number of times the linedef must be crossed before activation. It is recommended to make them as thin as you can, put one after other, and use them to connect two rooms.
  • Fix their floor height to be the same as the ceil.
  • Give them the sector tag XXX.
  • You might need to choose textures for the inner sectors.


  • This technique is limited to lower and raise sector heights.
  • If a player crosses the linedef again too soon, it may require more than N activations. The lapse of time is a function of the height of the N sectors.


LINEORD.WAD (file info) is an example of this trick. The player must fall five times to reach the exit. As the door is very tall, you must wait a little between activations.