Sidedef not divided into middle and lower texture

[DamTheGreat]

I made a lowering elevator. It is level withe floor above, so the linedefs adjacent to it would be untextured as it lowers, so I set a lower texture on them. I set a different one to the "middle" one that's on the walls on the floor it arrives at. The only problem: one of the three lines is not divided into "middle" and "bottom" textures. The entire line is considered "middle", even the part hidden by the elevator that only gets revealed when it lowers, so I can't put a different texture on that part. I tried erasing the line and redrawing it, but to no avail. Is there a way to force a split between middle and bottom texture parts?

(I'm sorry if I'm unclear, it's really difficult to describe in words what I mean, I'll try to elaborate if necessary)


EDIT: I'll add a screenshot to illustrate what I mean: the circled texture is the one I want to change, I thought it would be considered a "bottom" texture, as it is below the floor, but it's still considered a "middle" texture.

[Arctangent]

From the look of it, you're trying to apply a lower texture to a one-sided line. That's not really how they work - a lower texture is only applied to the edge of a higher floor, so a one-sided line won't ever show a lower texture because there's nothing for it to apply it to.

There's a trick you can use here, though, and that's to "collapse" the wall into a zero-height sector ( aka one where the floor and ceiling are at the same height ) so that you can split the wall with the lower texture and upper texture.

[DamTheGreat]

That trick worked, thanks.

[Gez]

To make it more explicit, the upper/middle/lower distinction happens when there are a sector on each side of a line. When there's a sector only on one side, then that line will only have a middle texture to show; including as you found out "below" the original height of the sector when it lowers.

When there are two different sectors on the sides of the line, then
- the upper texture is shown from the side of sector with the highest ceiling, corresponding to the span between the high ceiling and the low ceiling.
- the lower texture is shown from the side of the sector with the lowest floor, corresponding to the span between the high floor and the low floor.
- the middle texture is shown in the span where both sectors are "open" together; between the low ceiling and the high floor. The default behavior is that it's aligned from the floor, and does not tile; but that can be changed with flags.