Nice images, I like the colour mapping, lighting, and the crispness of kitchen modelling

You could try using either artisan or sculptris to create the type of drop you're after.

These are great, thanks

Thanks Stefan for your tips on map slots, been very useful! I managed to cook this up following your advice and Bertrand Benoit's 'materialism' post.

To clarify on the percentage contribution of the glossiness, I've found that once you plug a map into the glossiness slot this overrides whatever figure you use. In the example below is the same material with spec map and glossiness set to 1.0, 0.8 and 0.2 from L to R, it's not a great example scene but you can't see any diminished reflection as a result of the map being 'darkened'. If you drop the texture multiplier however, it blurs the whole thing rather than reducing the contribution of the map alone (shiny cube example), which means you have to go into photo editing software to finetune the map. This is a bit frustrating, if anyone knows a workaround within vray settings please share!

Model wise the first thing I fixed on were the 'sixty silver domes' so I drafted around 15 sections in CAD loosely based on domes such as Pantheon, Florence, Santa Sophia, then used 'follow me' to make quarter, half and full domes of the sections, then copied them to various scales and arranged. Same for the greek theatre type affair in glass on the right.

The scene was rendered in vray, to play about I turned the model upside down so the sun would shine into it from below. Materials are basic glass and metal. I rendered out reflection, zdepth and material ID and lighting channels then layered in photoshop something like this;
Reflection- blend mode overlay 20%
Zdepth- tinted purple to get evening haze effect, blend mode lighten 100%
Lighting- blend mode soft light 10%

I made a couple of dirt layers using the mat ID layer for masks and painted in with grunge brushes and decals from CGtextures. I also added some different coloured gradients to elements using the ID again. There's a dusky sky in the background which was adjusted to match the edge haze from the zdepth. People are brushed in using this technique;
http://vyonyx.com/tutorial01-creating-a-realistic-crowd-in-photoshop/
and statues are images I sourced and cropped adjusted etc to suit. I would like to draw my own statues in using the tablet but I fear my wacom skills might not be up to scratch yet!
Here's what the channels looked like;

The trick is (if I remember correctly).

1. Add your bump map using the sketchup material interface and paint the object(s) so the bumps are where you want them to appear.
2. In vray material dialogue, add a new diffuse layer to your material and pick the colour you want the material to actually be. Put this 'diffuse1' layer under your original 'diffuse' layer.
3. Back on the 'diffuse' layer, add a map to the transparancy slot and use the TexColour map, then pick white as the colour. This will make this layer invisible in the vray render but still visible in your SU window.
4. Tick vray bump map, add the bump map you used to paint with.
5. Et voila, when you render the bump should appear similar to what you see in SU window but with the colour you picked in the 'diffuse1' layer.

I think the UV coordinates you paint in the first step will apply to other map slots such as glossiness, reflection filter etc. So if you added another different map (say, scuffs or dirt to reflection) it will scale the same as your bump image.

I'll do a settings extract later if this is clear as mud.

Probably a lighting issue, have you tried resetting the options to default setting? It might help if you post your settings and an extract of your scene, as this could be caused by several things.

This probably wouldn't be quick, however if you're interested in modelling traffic paraphernalia to detail out your scene I've found most D.O.T. sites have a raft of standard details in CAD format for gantries, crash barriers, lamps etc.
http://www.dot.state.tx.us/business/standardplanfiles.htm
Example: ftp://ftp.dot.state.tx.us/pub/txdot-info/cmd/cserve/standard/traffic/stds66.pdf

Thanks for your comments, I hear what you're saying Dale, this image does have an equivalency of composition which flattens it out. It could perhaps do with some larger blocks or foreground element to up the contrast so that it might hold up as a value study, or (dare I say) achieve the chiaroscuro effect. Composition isn't my strong suit though I've been sketching a lot of Hokusai prints which should inform future images. I do still want to retain some sense of it being an worms eye architectural illustration with lines and a feeling of a technical assemblage of bits so I guess the key is finding a balance point.

It's been quite educational creating this so far and hopefully in time I can learn the light and thoughtful touch you speak of

Here's the first in a series of images I intend to produce illustrating Italo Calvino's 'Invisible Cities'. The first is Diomira, 'a city with sixty silver domes, bronze statues of all the gods, streets paved with lead, a crystal theatre, a golden cock that crows each morning on a tower.....when the days are growing shorter and the multicoloured lamps are lit all at once at the doors of the food stalls"

I've been trying to strike a balance between the concrete nature of some of the descriptions and the more poetic allusions to time and space given in the chapter by playing with recognised architectural forms in an abstract fashion. The aim of this is to give the images scope for multiple interpretations, as the original text provokes in the reader.