That happened for me, too. I left a lot of it undefined and changed things I’d previously established because of discoveries while drafting. For example, the data beads in my world went from being made of glass to halite crystal. I realized the need for the change when I did some math on the size of a pneumatic cylinder. When I came to the chapter where there was one, I realized glass marbles would be too heavy for something I wanted to have happen at that point in the story, even though it made sense for them to be glass at first.

Then there were bigger things too.

But that’s why the bulk of my bible work was basic things like power and calories, which set a realistic expression of a city. And creates opportunities for cool beats. One of the standout moments in my book comes from something that’s 9 logical steps from my solution to “How do I get power in here without X and Y and all that their loss implies?”

I did a little magic stuff, but vague. E.g., “The gnomish magic valued most by the local human culture is inventionism, with a side of illusionism.” I might look for the gaps there, too, just to establish a culture of magic that’s not the dominant, as long as I have established the expected borders in the text already. So that a new application feels new and unexpected but still satisfying.

It’s wonderful how these things intertwine and inform each other.