-lowmem Uses scaled-down textures and lower quality (8-bit) sounds to conserve memory.
-superlowmem Uses the "-lowmem" settings and further scales down textures to conserve memory.
-himem Forces normal operations even when low memory conditions are detected.
-vsync Turns on Vertical Sync. The flag will be enabled in the registry so it will be on when the game is run again.
-mouseman Enables special handling for the Logitech MouseMan.
-chpro Enables a CH Flightstick Pro or compatible joystick.
-width <width> Sets the screen resolution to the specified width, if possible.
-height <height> Sets the screen resolution to the specified height, if possible.
-nonetwork Disables all network multiplayer functionality.
-nosound Disables all sound, including music.
-nomusic Disables music.
-nointro Disables intro movies.
-nolightmaps Disables lightmaps. This will improve performance on low-end video cards.
-forcelightmaps Forces the use of lightmaps, even the Default Detail Level is set to low in the launcher setup.
-nomultitexture Disables single-pass multitexturing. This option
could fix problems due to buggy drivers on future video cards.
-nooutdoorfog Disables fog on the terrain under Direct3D. This
may improve performance on some cards.
-nooutragelogo Turns off the Outrage logo on spawn-in
-setdir <path> Specifies the working directory for Descent 3.
-useexedir Tells Descent 3 to use the directory in which the
executable is located as the working directory.
-alternatejoy Causes DirectInput to be used for the joystick
-directinput or other game controller, instead of standard
Windows API. Some joysticks need this option
to work with Descent 3.
-pilot <name> Specifies the pilot to use, skipping the pilot
selection dialog when the game starts.
-aspect <value> Specifies the screen aspect ratio for
non-standard displays, such as wide-screen
TVs. The aspect value is the width of the screen
divided by the height, so if you want to play
Descent 3 on a 16:9 wide-screen TV, use
"-aspect 1.78".
-framecap <fps> Limits the framerate to the number of frames per
second specified. Descent 3 defaults to a cap
of 50 FPS. To remove the cap, use the
command-line option "-framecap 999".
-makemovie Causes the demo system to save a screenshot
of every frame during playback. These saved
frames can be used with video creation software
to make a movie. NOTE: When recording a demo
for use in making a movie, you should use the
"-framecap" command-line option to specify the
framerate of your movie.
-fastdemo Causes a demo to play back at the highest speed
your computer is capable of, and to display some
performance information when it's done.
-timetest <file> Causes Descent 3 to play back the specified
demo file upon startup. When the demo is done,
the game will exit and create a file called
fps.txt which contains detailed performance
information.
-highvidmem Causes 2 MB Voodoo 1 cards to behave as if they
had more memory. This will increase visual
quality but may cause framerate problems. This
option has no effect if you use OpenGL or
Direct3D.
-subpixelcorrect Adjusts for subpixel correction under Direct3D
for cards that do not support it. You can tell
if subpixel correction is not supported if your
main menu initially has lines in it like a
tic-tac-toe board.
-nocompress Turns off S3TC texture compression for cards that
support it (such as the Savage3D and Savage4).
Texture compression is on by default for these
cards.
-bumped Enables hardware bump-mapping on cards that
support it, such as the Matrox G400.
-NoRenderWindows Causes all windows to be fully transparent. Use
this option if your card does not correctly render
partially-tranparent windows.
-z32bit Enables the 32-bit z-buffer on cards that support
it, such as the Matrox G400.
-autoexec <file> Specifies the the full path and file name of the
multiplayer config file (eg., autoexec.dmfc) to be
loaded and executed when a multiplayer game is
initialized. This is useful when running more
than one dedicated server on one machine.
-deadzone0 <k> Specifies the size of the deadzone for a joystick.
-deadzone1 <k> k is a value from 0.0 to 0.5 sets the deadzone
to the specified fraction of the total joystick range.
-deadzone0 sets the first joystick and -deadzone1 sets
the second. For example, "-deadzone0 0.2" sets the
deadzone for joystick 0 to 20% of its total range.
-nomotionblur Disables motion blur on robots (Pentium III only).
-nosparkles Disables powerup sparkles (Pentium III only).
-nopentium3 Disables detection of the Pentium III processor.
Some early P3 machines may not work correctly with
Descent 3; if you have troubles, try this option.
-mlooksens <scale> Determines how much the player moves when the mouse
is moved. The default value is 9.1; smaller values
give more precision.
-mission <name> Causes the specified mission file to be loaded at
program start, and makes that mission the default
when starting a new game.
-mousesens <scale> Adjusts the sensitivity of the mouse when not
using mouselook mode. A value greater than 1.0
makes the mouse more sensitive; less than 1.0
makes it less sensitive.
There ya go.
*this does not include Server command lines.*