Factorio Forums

This is a follow-up from a bug that Rseding partially fixed back in May.

When placing tiles over cliffs that collide with them some cliffs are removed. Others aren't.
It does work correctly when placing from the editor. So I assume Rseding only fixed it from there. But I'm not sure.
The previous bug report ended with Rseding saying:

Rseding91 wrote: Tue May 06, 2025 4:34 pm [The cliffs] should [be removed]. If the tile collides with the cliff it will remove the cliff - as intended. Any colliding entity gets removed when a colliding tile is put under it.

I replied to it back then with that this seems inconsistent with other entities. All other entities I tried, the tiles just aren't built under them: But even if it's intended. Shouldn't all cliffs be removed instead of just some?

In any case. I've set up a small test world with a related mod where concrete collides with concrete for easy testing (see attachments).

So the underlying issue with this is not addressable in any reasonable way. However, I can change the cliff bounding box sizes *slightly* which will at least make the base game ones not get removed in this scenario.

However, if another bug report shows up about other issues caused by the changes then I'll likely revert these ones and call it a day. Bounding box tweaks are extremely fragile and very commonly break something else.

Actually I can't change the cliff bounding boxes as it will cause some existing saves to break if they've built next to cliffs. You're free to tweak the bounding boxes in the mod that's also making tiles collide with cliffs. The root issue is any entity that touches a tile edge exactly. Increasing or decreasing the bounding box of the entity to get it off tile edges will prevent the changing of tiles from destroying the entities.