Best way to do a horizontal moving platform?

I'm only guessing here because I have not attempted such a feat, but I'd imagine a model of your platform would work well. Then simply use actor movers to move the model in space.

Depending on what you want, a polyobject with attached portal might also fit the bill. In EE / UDMF, you first define a polyobject like normal and then use Portal_Define to attach a portal. To link eg this portal's ceiling back into the containing area (the area that has the polyobject anchor), use that portal id in the ceilingportal sector property.  GZDoom has probably something similar.

Check out Gooberman's Floor_Demos

https://www.doomworld.com/idgames//index.php?search=1&field=author&word=gooberman&sort=time&order=asc&page=1

Discussion was here:

https://forum.zdoom.org/viewtopic.php?f=37&t=47205

@Kappes Buur, Nice, it seems he's using both poly and 3dfloors to achieve the unthinkable.

Definitely considering Poly's now.

But perhaps there is still a better way? 

@Mordeth, You know I thought about polys at one point and actually considered them as a real world scenario as well until, I remembered how tricky they can be to setup especially when in this case the moving platform object will essentially have to function like a bridge where other actors can freely move over and under and ride on it. Yet I still consider it, and probably should have mentioned poly objects.

13 hours ago, Nevander said:

I'm only guessing here because I have not attempted such a feat, but I'd imagine a model of your platform would work well. Then simply use actor movers to move the model in space.

This seems as it would be more of a standard way of doing it, actually.

I'll wait and see what others come up with, as I'm looking for the best and hopefully easiest way of going about it.

I should probably also ask for examples.

If we come with a good working version, then I'll try my best to optimize it to the point where such goal can be setup with in a few steps.

It seem there needs to be a standard of some sort anyway.

Edit:

So far it seems this is a best way to go about it what I'm looking for, found here:

https://forum.zdoom.org/viewtopic.php?f=37&t=47205

Thanks to Kappes Buur for the source link!

Uploaded a zip containing the same file here:

platform_demo_5b.zip ~ though literally is programed to function at all, it works well. 

Yet I'd like to keep this unanswered for a little while incase someone else has an even better way to achieve this. ;)

Because as far as we know someone may already be working on something new. :)

No volunteers? 

I'd like to get an eye on @Nevander's theory of using a model, and actor movers.

A basic 128x128x32 platform model should do.

What's everybody's scope on this?

Thanks