Hi Sneer,
Really the entire system needs refining because currently the TOD curves are mostly a function of the lat/long and time data.
Technically we should only really need a few curves...
I'm not sure what a shininess curve would do though? Would you care to elaborate on what you feel is missing?
The sun specular is currently tied to sun diffuse colour since technically they are the same thing.
It's good to see you use colour grading though. Real values for ambient/diffuse colouring are quite blue tinted on clear sunny days, so I've used colour grading to kill out the blue tone of the rendering.
Ideally I'd like to see a TOD curve that was white balance (red/blue shift basically), so you can tweak the white balance across the TOD.
But really the mie/ray sky rendering is currently not so great (seems low definition somehow) so for now the entire thing is a bit iffy if you want a dynamic TOD system working.
I'd love to see full 24hr TOD system working but Ruud really needs to start from scratch with some of the systems to make that work elegantly imo. The current system is 'ok' but far from convincing vs all the new sims coming out these days with fantastic graphics lighting and shading (ie, GT6, Drive Club and so on)
Given the basic shaders and TOD limits I think you've done a great job though.
Hopefully in a month or so I can get back onto working on the track with Stereo that we started and we can post up some newer shaders/track content that will hopefully show some more interesting ways of approaching track lighting/shading... I think you'll be impressed
Dave