The EU4 devs have been using forum suggestions to aid gaps in AI development

One fan in particular managed to reverse engineer AI behaviour in a way that was easier to understand than the code itself

The developers at Paradox Tinto – the Barcelona-based studio that’s dedicated to supporting Europa Universalis IV – are hard at work on the next round of content updates for the grand strategy game. The studio has also been trying to staff up so that there is dedicated support for tackling every aspect of the game’s design, especially the AI.

Studio manager Johan Andersson tells us that his team only recently welcomed an AI programmer to keep working on the game’s complex coding, and one key part of bringing staff members up to speed was suggestions from the community themselves.

“There was basically not much knowledge left about how the AI code worked because there had been so much turnover on the EUIV team,” Andersson explains. An example of this community-sourced knowledge can be found in the most recent dev diary for the game, which gives special thanks to several members of the fanbase. One of the major fixes to AI behaviour coming in patch 1.32 was suggested by a forum user named Tempscire. The dedication reads: “A special shoutout to Tempscire, whose reverse engineering of AI army behaviour is somehow easier to understand than the code itself.”

The post also notes that while some parts of Tempscire’s new idea for AI behavior have been implemented, other elements have had to be tweaked for “technical reasons”.

The dev diary – which was written by Andersson – finishes off the shout-out by stating: “Unfortunately [they have] many other good suggestions that will not be implemented at this point.”

Tempscire’s fix is part of a wave of changes coming to AI behaviour, and the new patch brings a bunch of other welcome additions as well. Institutions are getting reworked, which will be great for nations outside of Europe, and AI colonisation efforts will be aided.

The diary also talks about some of the difficulties relating to AI design in EU4, which illuminates why implementing change is so difficult: “EU4’s AI is the product of years of incremental development, by a large number of developers,” Andersson states.

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“Most of the code is written after EU4’s release, but a few lines date back as far as the late 90s. Writing AI is hard, so many of the systems are complex. And given the number of different developers, they don’t all work in harmony. Essentially, for any given choice the AI has to make… it often has a dozen or so voices in its head telling it what to do. It’s supposed to take all of them into account, but often the loudest drowns out all the rest.”

So while the experience of long-time fans (especially those who happen to know the right skills) has been instrumental in assisting Paradox Tinto in the short-term, these suggestions must also be balanced against the fact that some things are not so easily changed.

The next Europa Universalis IV DLC expansion will focus on sub-Saharan Africa, as well as the 1.32 patch. At the time of writing, the patch is expected later this year.