I played DOW quite a lot around 2006ish. I bought DOW2 a couple of years ago and really like the detailed Imperial cities, and the graphical representation of Eldar stuff as well as Imperial. So there is established graphical material available in CGI out there.
But I don't think Erasmus used any of it. This prologue is set on Holy Terra, and he's done a great job.
Looking forward to the rest.
Oh and there's this as well:
Which looks great. I really quite admire people who do this type of thing, especially when they do it this well..