I'll quote myself from the Barbagallo topic (read that one as well, basically all of that should be relevant for you as well):
Quote
...a general tip: if you build elevations before you're done with things you can read from your baseline image (layout, track width, kerbs, bank widths, verges and pitlane layout), you are essentially wasting your precious time, because then when you want to proceed to the remaining items from the above list, you won't be able to place them on their proper spots. So, the tip would be: insert the baseline image, draw the initial layout, align the track width where needed (in the case of Barbagallo, maybe in Turn 4 first and foremost), place the kerbs, create the properly-sized run-off areas (I hate that part, haha, I find it way too time-consuming :D), and do the pitlane properly. After that, you can start building elevations which would then raise and drop your .dat from the surface of your baseline image. Also, your previously created parts, kerbs, rail alignments might provide help when you come to nail your elevations.
So it's basically
- Layout
- Width
- Banks
- Verges
- Kerbs
- Pitlane
And then the elevations, bankings and the rest. You can create basic CC-lines earlier (as you did), but you should only nail them after you are done with the elevations - this way you will know at exactly which sector the track goes through a crest or a compression, so you will be able to adjust your lines accordingly.
My workthread - [www.grandprixgames.org]
Full of classic F1/non-F1 track layouts
My blog about F1 performance analysis - [thef1formbook.wordpress.com]