How To Make Doom .lmp Demo's Last Change: 28/Jun/96 By Ian Mapleson (mapleson@gamers.org) Acknowledgements: bontchev@informatik.uni-hamburg.de (Vesselin Bontchev) - for info on time limit and net game reminder. First of all, what IS a .lmp Doom demo.? In Doom, Ultimate Doom and Doom II, it is possible to record a playing session; ie. you can save to a file exactly what you do during a chosen episode and level/map (these demo files have a .lmp suffix). This file can then be played back later so that you can sit back and watch exactly what you did. The file itself does NOT contain any graphics images. The demo file merely records which keys get pressed and also the various mouse movements. However, there are certain key actions that are NOT recorded. These include using the ESC key to bring up the main menu and any actions taken using that menu. Also, you may find that using the mouse is not _quite_ as smooth as when playing normally - this is probably due to the overhead of having to record the various mouse movements as you play. One annoying thing is that the game _will_ record any use of the PAUSE key, so make sure you don't use it when recording a lmp file. Note: As a general rule, demos recorded on one version of Doom (say v1.2) will not work run properly on another version of Doom (say 1.666). This is because of changes in maps between versions, changes in the rules governing monster behaviour, differences in the format conventions between versions, etc. Some of these things can be worked around by a little bit of hacking (post to rgcd.editing for more info). HOW TO RECORD A .lmp DEMO.: All the commands shown here should be typed whilst in the same directory which contains your Doom files. The general command for recording a .lmp demo is as follows:- doom -devparm -warp -skill -record [-respawn] Where: is 1 for the shareware version, or 1 to 3 for the registered version, is 1 to 9 (level 9 is always the secret level, although the actual from which you get _to_ a secret level is never level 8), is 1 to 4 for v1.1, or 1 to 5 for v1.2, is the name of the file that the demo is to be saved to. NOTE: the '.lmp' suffix MUST NOT be included in the file name. If you _do_ include it, Doom will not be able to find the file! For Doom II: I should imagine that the ' ' combination would be replaced by a single number from 1 to 32 when making recordings in Doom II. You might have to include a preceeding zero for level numbers below 10 (ie. use 01 to 09). Try it and see. The option '-respawn' may be included; this makes the bad guys regenerate each time they get killed and also makes them faster, more accurate with their weapons/fire balls, enables them to shoot more often, etc. Thus, running Doom on skill level 4 with the -respawn option gives a level of difficulty kinda half way between 4 and 5 (where 5 is Nightmare mode). If you start the game in Nightmare mode, the '-respawn' option isn't needed. Note: there is a time limit in versions of Doom <= 1.2 of about 15 to 17 minutes. It depends on exactly what you're doing as to how fast the demo buffer file fills up. There is no limit in v1.666 (and higher) of Doom; the demo will simply terminate if the buffer space is exceeded, but that would be after a lot of recording. In v1.666, I understand one can also specify how much space to allocate to the demo recording buffer. Precise info on this will be in the README file that comes with the game. Demo making examples... Example 1: (this won't work on Shareware Doom because of the episode and level used, so try something like episode 1 level 4 if you're a Shareware user...) Record a demo of the Cyberdemon (Episode 2 Level 8) on skill level 3, saving it to a file called 'mydemo1.lmp'... doom -devparm -warp 2 8 -skill 3 -record mydemo1 . /|\ | Note! NO SUFFIX! Example 2: Record a demo of The Unholy Cathedral (Ep 3, lev 5) on Ultraviolence with respawning to a file called 'e3l5resp.lmp'... doom -devparm -warp 3 5 -skill 4 -record e3l5resp -respawn Example 3: Record a demo of the secret level on Epiosode 1 (The Military Base) in Nightmare mode, to a file called 'e1l9ntmr.lmp'... doom -devparm -warp 1 9 -skill 5 -record e1l9ntmr PLAYING BACK THE DEMO: The general command to play back a demo file is: doom -playdemo Where is the name of the .lmp demo file, BUT WITHOUT THE SUFFIX! If the '-respawn' option was used to make the demo, it must be used when playing back the demo (thus, the option is NOT needed for Nightmare mode demo's). Thus, for the three examples above, they would be played back with the following commands respectively: doom -playdemo mydemo1 doom -playdemo e3l5resp -respawn doom -playdemo e1l9ntmr When making a demo recording, you can save it at anytime by pressing Q. The demo also terminates when you get to the end of the level. If you die, then press Q to save. F10 will quit without saving. I understand that versions after v1.2 will also record the end-of-level screen so that you can see what the scores were. USING THE DEVPARM PARAMETERS BUT NOT TO MAKE A DEMO.: You can use the various devparm parameters to start a game off from a particular episode and level _without_ making a .lmp recording. This is done by not including the '-devparm' option, ie.: doom -warp -skill [-respawn] The various parameters are just the same as before. Other notes: Trying to use ANY of the cheats when making a .lmp demo, will HALT the demo! One thing to remember, therefore, is that since the demo is going to STOP at the end of the level, there is no need for you to 'conserve' ammo for the next level. However, the PAUSE key _does_ get recorded during demo making, so try and make sure you don't get interupted by anything during play. You cannot save your position during a demo recording session. Pity... :( At least not in v1.2 anyway and I don't think this has changed in later versions. Correct me if I'm wrong. Anyway, that's all I can think of at the moment. Have fun! :) Ian. The Doom Help Service (DHS). SGI Network Admin, University of Central Lancashire, Preston, England, PR1 2HE. Tel: (+44) 01772 893297, Fax: (+44) 01772 892913 | Doom: mapleson@gamers.org Office machine: SGI Indy R4400-200Mhz/1MB cache | Misc: mapleson@cee.hw.ac.uk 64MB RAM/2GBdisk/24bit 17" 1280x1024/CDROM/DAT/IndyCam | --ACME Space Filler--