Rising water Edit
Here's the process for a rising water effect, for example a room being flooded.
- Make a func_door which will be your liquid and texture it with a water, slime, or lava texture.
- Place the func_door where you want it to be after it has moved and set the "starts open" and "crusher" spawnflags.
- Set the lip key of the door to the distance you want the water to rise, but make it negative (eg -128). This tells the engine to move the water 128 units down into its 'open' position where it will start (because we set the "starts open" spawnflag).
- Set the angle key to -2 so the door will move down into its 'open' position.
- Target the func_door with another entity such as a func_button or trigger_multiple which will cause it to rise.