How do I make an invisible platform or a solid invisible/glass sector wall without the "impassible" attribute in Boom?

[Ar_e_en]

I primarily want to know about the solid invisible/glass wall, but the invisible platform might be useful for me to know as well.

Is the invisible/glass wall as simple as just lowering a sector to the floor and not applying any texture to the sector walls, or is there something else that I should do or keep in mind?

 

[boris]

Since you're targeting Boom the easiest way is to use the 242 action: https://soulsphere.org/projects/boomref/#ld242

 

See attached example map. The way to the megasphere is blocked (where the FIREBLU is), pressing the switch opens the way.

invisiblewall.zip

[Stabbey]

Do you want the player to be able to pass under the invisible wall/platform, or should it be solid even though you can't see it?

 

If you want the player to pass under it, that requires a 3D floor. If it's solid, you make a pair of sectors for the platform, one inside the other. The inner platform should have all its linedefs pointing inwards. Each linedef has a sector number associated with front and back. Front is side the linedef is pointing into, back is the opposite side. All the linedefs on the inner sector should have their sector number set to the outer sector. This is known as a self-referencing sector.

 

Keep in mind that this will likely only look proper if you can't see the top of the platform. Otherwise, it'll look a little glitchy. If you're only viewing it from below, it will appear invisible.

[ViolentBeetle]

You can use "create fake floor/ceiling" linedef type to make tagged sector draw at the height on the sector in front of linedef.

 

Untextured walls will work well as long as the floor/ceiling that's supposed to be hidden is out of sight.

[Ar_e_en]

4 hours ago, boris said:

Since you're targeting Boom the easiest way is to use the 242 action: https://soulsphere.org/projects/boomref/#ld242

 

See attached example map. The way to the megasphere is blocked (where the FIREBLU is), pressing the switch opens the way.

invisiblewall.zip

The example map is a nice touch!

 

4 hours ago, Stabbey said:

If you want the player to pass under it, that requires a 3D floor. If it's solid, you make a pair of sectors for the platform, one inside the other. The inner platform should have all its linedefs pointing inwards. Each linedef has a sector number associated with front and back. Front is side the linedef is pointing into, back is the opposite side. All the linedefs on the inner sector should have their sector number set to the outer sector. This is known as a self-referencing sector.

 

Keep in mind that this will likely only look proper if you can't see the top of the platform. Otherwise, it'll look a little glitchy. If you're only viewing it from below, it will appear invisible.

I think I get the gist of the sector trickery there, but it's still kinda hard to get my head around it.

[Ar_e_en]

5 hours ago, Stabbey said:

Keep in mind that this will likely only look proper if you can't see the top of the platform. Otherwise, it'll look a little glitchy. If you're only viewing it from below, it will appear invisible.

Wait, I swear that I've seen other Boom/MBF/PRBoom-Plus maps use the invisible platform trick without the glitchy floor. Is there something more specific there that I'm missing? I think that even REKKR used some invisible floor tricks in the bonus 4th episode.

[Stabbey]

Oh, those ports have advanced features which can do that better. It's vanilla compatibility with the glitch problem.