Factorio Forums

TL;DR

An event that is triggered when the engine's built-in "Cannot build on [surface]." error is shown (Ex: "Cannot build on Grass 2")

What?

While looking into a suggestion made in my buildings on concrete mod about having heavier/more sophisticated buildings require more sophisticated tiles (such as reinforced concrete for foundries instead of stone bricks), I hit an engine limitation where either I break blueprint functionality or it would be very obscure for the player to know what kind of flooring the building requires.

This particular error

does not trigger an event and I have no way of coupling either a custom error such as "Iron Chest must be built on solid flooring". I have worked around it by editing the localized name to "Cannot be build on Grass 3. Must be built on solid flooring" which somewhat works for now that all buildings must be built on any kind of solid tile.

However, if I would like to restrict bigger buildings to better tiles, I cannot use that workaround anymore and the other option to implement would wreck performance and the blueprint system (currently shift+click places the tiles under the building like landfill on water)

Why?

I believe more API hooks for currently internal engine events would benefit the game by providing even more modding possibilities

Thank you for your time

Duplicate of viewtopic.php?t=102963

That was four years ago, perhaps the situation changed

Zenyatta2011 wrote: Wed Jan 21, 2026 6:30 pm That was four years ago, perhaps the situation changed

It didn't.