Linedef type 173, Crumbling, No Respawn, Intangible from Bottom, is a type of floor over floor platform which will crumble and fall one second after being jumped or stepped upon by a player. It can be jumped through from below, but is solid to anything landing on it from above. Unlike linedef type 172, this platform will not respawn after crumbling. It is useful for creating sections where the player needs easy access to platforms from below, but should only have one attempt at getting through the area.
Setup
The flats, floor height, and ceiling height of the FOF are determined by the flats, floor height, and ceiling height of the control sector, and the sidedefs of the FOF's walls are determined by the sidedef of the control linedef.
The light level of the control sector will determine the brightness of the shadow cast by the FOF. If the light level of the control sector is lower than that of the target sector, then it will cast a dark shadow. If the light level of the control sector is higher than that of the target sector, then the FOF will illuminate the area below it. If the light level of the control sector is equal to that of the target sector, then the FOF will not affect the light of the area below it.
If Flag [6] / Not Climbable is checked, the FOF will not cast a shadow.