Shadows casted on bridge tiles

[zzattack]

Does anybody know how the game knows which subtiles of a bridge tmp can have shadows casted on them?

In the game, tiles that have a green + on them have shadows casted on them, tiles that are marked with a red - sign on them do not.
Does anyone know how this is determined by the game? Can I somehow tell the game not to cast shadows on a certain subtile? Is z-data used at all? Thanks for any answers.

[Blade]

The first bridge overlay is placed over the centre tile out of the ones you marked green. The overlay is drawn to cover the 5 cells marked and so they get their shadow like all cells under the bridge overlay.

[zzattack]

Thanks Blade, what you said is entirely correct. In my map rendering tool I need an offset for bridge overlays, however it apperas this offset was reversely applied to the shadows casted by these bridges, resulting in them seemingly being casted on different tiles. I had spent quite some time on this already, but after I read your post I got it figured out in a minute. Thanks again.

[Marshall]

Completely off topic so I apologise but it's "cast" not "casted". "Casted" isn't a word.

[Tempest]

lol, you're remindind me of my CPE teacher..