3D Floor ceiling disappears when moving down a slope

[SPZ1]

Exactly what the title says! I was thinking that I could recreate the sloping lift in games like Half-Life 1 or Doom 3.

[Graf Zahl]

This cannot work. You have intersecting sector planes and the engine cannot handle such a setup. The single most important rule for 3D floors is that they must not intersect with each other or with the sector's own ceiling or floor. To do efficient processing, 3D floors must be strictly ordered - and the ordering must be the same in all locations of the sector. It uses the center as reference so once the 3D floor moves below thew sector center's z it will no longer be rendered because the engine thinks it is out of view.

[SPZ1]

Thank You for the insight then!