Are there hidden requirements for certain buildings and structures?

[Glade]

I ask because many times I have not been able to build ports and upgrade wooden castles when i should have. I have noticed that you get the option to build things like a forgery when you've reached a sufficient armor upgrade level (and maybe get a swordsman's guild) so i was wondering if it was because i haven't build a required structure to get a port.

[ivanhoex]

read the PDF that comes shipped with installation, it sits in the main folder of Medieval Total War

[Glade]

I see, I need a market place. Still, that doesn't explain why I often cant get the option to upgrade wooden castles with a population of over 3.5K.

[ivanhoex]

read the same pdf, but further and with more attention

[Glade]

I seriously cant find it. Could you help me out?

[Crimson Scythe]

If you go to the building browser and hover your cursor over any upgrade building, it'll list the pre-requisite buildings.

I believe you need the second barracks building to upgrade from a wooden to a stone castle, in addition to having more than 2000 population.

[Furin]

The easiest way to see if there are requirements is to open the edb (export_descr_building.txt) and take a look. If you are unsure what a certain line does a visit to the mod workshop usually provides the answer.

Let's see, castles, you are most likely talking about the last upgrade level, Citadel.

citadel castle requires factions { northern_european, middle_eastern, eastern_european, greek, southern_european, }  and event_counter governor_present 1 and hidden_resource metropolis and building_present_min_level castle_barracks barracks

So what exactly are the requirements?

event_counter governor_present 1 ... you need a govenor in it (love how this was implemented)
hidden_resource metropolis ... the crux of the matter, a resource not visible on the map like the trade resources, defined in descr.regions
building_present_min_level castle_barracks barracks ... on top of that a barrack structure of sufficient development

So castles are limited by event (time), resource and structure.

[Glade]

Thanks for the tip guys. Actually i was talking about the wooden castle upgrade to stone castle. I knew about the metropolis requirement but i appreciate the help nonetheless.