Linedef type 104, Solid, No Sides, is a type of floor over floor block which renders the flats but not the sides. It is primarily used for FOFs whose sides will not be in view anyway, as a means of reducing the CPU power required to render the level.
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.
If Flag [6] / Not Climbable is checked, this FOF will cast a shadow beneath it. In this situation, 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.
Linedef special info
Floor height
Height of bottom of FOF
Ceiling height
Height of top of FOF
Sector light level
Brightness of shadow cast (If [6] Not Climbable is checked)