How in the forget are you doing this with sketchup?
A combination of skill, attention to detail, perfectionism, and having way too much time on my hands. Sketch-Up really resonates with me, I find it enjoyable, and because of that I can put hours upon hours of work and tweaking into a model without ever tiring of it.
However, this actually reminds me of an idea I had a while ago: why don't I show you?
I'll put up a livestream of me modeling later today on Twitch.tv, probably around 4 PM or so. I'll post a link to my channel here when I start streaming.