Ah, Yes. I use to have a strong mental model of our security infrastructure and could troubleshoot problems by just hearing the description of the issues and a couple of variables. I would literally see visual gaps where my knowledge of the system stopped if I was drawn there. I would then fill in those gaps.

Now as a developer I haven't worked on a model long enough (my excuse) to be able to do that. But now I realize I already have a process for identifying gaps that I don't use.

I work with a guy who can do this and recently he has amazed me with how he can do it. Contrary to this though, sometimes I think he works in outdated models that limit his creativity.

I am beginning to realize this recently at my new job. Due to a couple of people leaving and stuff like that, i got handed a reportedly(half-written) code base with no test cases. And a knowledge transfer document, that was mainly written by a poor guy who had gotten the code(before me) and left the project in 3 weeks. In any case, couple of months into the project i got handed a different requirement. Guess what, a total of 10 months after i took the job the second tool is done and is in testing while i am still working on the first one. But the main problem so far has been, lack of clear visualisation of the requirements beforehand. Documenting a project specifications (functional or technical) is unheard of here it seems. I swear taking the time to gather all the requirements would have halved the time i spent developing,demoing, getting feedback,correcting/fixing suggestions etc.. sigh