Fascinating. In an earlier life I worked as a graphic designer and always felt I had a keen ability to accurately visualize the art in my head before putting pen to paper, so to speak. But never like having a canvas in front of me, definitely more symbolic like you describe.
I'm not sure I can completely relate to your experience with needing CAD, other than I've noticed that sometimes the real world is flipped to my mental model, which can lead to funny results when my actions are backwards. I can usually 'visualize' things like that, at least in some abstract sense.
Well, that is, except specifically when it comes to my bother and father. They can somehow explain things to each other and know exactly what they are talking about with ease, as if they have some kind of telepathic link. They can say the exact same thing to me and I'll have absolutely no clue as to what they are talking about until they draw a picture. Now you have me curious to know if they are able to score 6.