I can pretty much visualize things as if they were in a 3D modeling system (there may be a reason why I work in mechanical product design). I can take some object and imagine it flipped around to another orientation or imagine how a complex mechanism will operate. I'm so adept at doing this that I very rarely actually draw things out before I start doing CAD work.

I would say my ideation process starts with a vague view of what I am trying to accomplish, and then gradually becomes clear. I'll have a general concept and can picture the end result, but without understanding how it is accomplished at first, which gradually becomes clearer as I think about it. I generally know I've got something when it "feels right".

My main artistic hobby is photography. One of the things I most enjoy doing is going out without a specific shot in mind and trying to "find" a photo by deliberately experiencing my surroundings. It is almost have an aversion to have a shot in mind before I go out to take it because it invariably doesn't live up to the visual I have in my head.