Question/possible feature

Question: Do the platforms hold up dumped material? If not could they? Could make makeshift tunnels if combined with retaining walls if that was the case.

Interesting question

Not possible, unfortunately, and not something a mod can add. The game's terrain is a heightmap: every tile has a single surface height and a stack of material layers below it, so ground is always solid from the bottom up. "Dirt on a platform with a hollow tunnel underneath" simply has no representation in the engine.

Probably they mean that if I dig through a mountain in one direction, place a row of platforms like a tunnel, and then fill everything back up (for example, with stone), will the platforms break? Will they be unable to withstand the weight of everything dumped on top of them?

Or is there a way to make it so that if I dump the mountain back on top of them, the platforms won't break?

The idea itself of using such platforms to make tunnels through mountains is great. You could use them (if they can be made indestructible), or come up with something similar in appearance. You probably wouldn't even need to dig initially — you could, for example, mark the construction of platforms straight through the mountain, turning them into a tunnel, and the excavators would start digging out the space inside these platforms, removing the rock from there. The only thing is that the side walls of the platforms shouldn't let any rock inside. And voilà — the tunnel is ready!

Ahhh, I get what it means — that the engine itself doesn't support having a void underneath a surface, for example, under a layer of stone — meaning a hollow area :(((

And, for example, if it's possible, could you create a surface (or layer) that is kind of invisible, and that vehicles can drive through, and when excavating rock inside the platform, it would essentially replace that rock with this surface (layer). Sort of "trick" the engine by swapping the surface or layer so it doesn't complain.

Umm you are aware that the question was understood and answered already?

Of course, I understand. I just decided to add a comment, just in case it adds something and gives you an interesting idea on how this could be implemented. If it's possible at all.

I apologize if this might have bothered or offended you in any way :)