A tutorial for GZDoom

A 3D building with a proper roof

The conventional way

The roof of this building consists of a simple 3D floor and 4 sloped 3D floors. To achieve the sloped roof notice how the control sectors are aligned with the play area. For the slopes to occur add a sector with the approptiate height and set the common linedef to 181:Plane_Align.
For example:

3D-01-01b (201K)

The result is this

3D-01-02 (502K)

Example pwad: 3D-01a.wad

The problem with the above setup is immediately noticable in large maps. The control sector for the alignment has to be constructed in a void fairly closeby, which is not possible in most case, so must be constructed far away at the edge of the map, which makes the alignment a bit tricky.

Done with the 3D_Floor plugin for UDMF

To the rescue comes boris's 3Dplugin, which accomplishes the alignment of the slope in the sloped sector itself, with a control sector somewhere on the side of the map.

3D-01-01c (282K)

Example pwad: 3D-01b.wad

It may take a few moments to get the hang of how the plugin works, but the effort is well worth it.

Link to original forum post

Happy fragging.
Kappes Buur, Sept. 09, 2017