Make Transparent flats not solid?

[Graaicko]

Hello. I recently discovered how to make see through ground flats and such. I was wondering if there is a way to make it not solid. For example. I would like to create a toxic waste pit and have the flat act as a liquid that you can somewhat swim in. (I do not want to make it a water sector.) To narrow it down I'm essentially trying to make it act like when you break a ground vent in DN3D.

[ReX]

... I would like to create a toxic waste pit and have the flat act as a liquid that you can somewhat swim in. (I do not want to make it a water sector.)

You've said "liquid that you can somewhat swim in", and also said "I do not want to make it a water sector". It's unclear to me what you are trying to create. [Your DN3D reference reference didn't help; all I remember is that you could blow up manhole covers to jump into the pits below.]

If you're asking how to make a liquid in which you can wade, simply make the liquid pool shallow. But I suspect you're not asking for this.

[Graaicko]

Yeah I know. It's hard to explain what I want due to not knowing what this process is called. I was describing what it looks like visually. Lets put it in my terms. I create a transparent catwalk using the 3d floors action, So it's a flat 3d floor but I want it to act as in your a swamp for example. The 3d floor does not react to player collisions and is pretty much a hidden sector in the ground by a 3d floor flat.

Heres a direct example of what I'm trying to do: https://youtu.be/O7o67zUjvfQ?t=37

[Gez]

A 3D floor's opacity is entirely disconnected from its solidity, you can make an opaque 3D floor that you can pass through and a transparent (even invisible) 3D floor that you can't pass through.

You can make a shallow pit with a high friction so that player movements are slowed down, and put a non-solid transparent 3D floor on it to make it look like water, and without making it a water zone.

[ramon.dexter]

The shallow water effect could be achieved through TERRAIN lump. At least I'm doing it that way.