Hi Richie. Ok, I still doubt 3D could ever compete with the lower costs and quality of injection moulded plastics employed for volume production, but for one offs or very small volumn it does seem to be gradually improving. I've seen some well finished WSF Shapeways models of UK stock that weren't entirely on a different planet to RTR. Recently I've acquired some Shapeways FUD (frosted ultra detail) which surprised me for quality and smoothness bordering in IMP. No evidence of 'tooth paste' effect whatsoever.
As you know I recently did a 3d loco but it was Shapeways WSF which indeed had some 'tooth paste' effect that I choose to rub down and fill with Halfords grey primer, but the FUD material seems a vastly finer resolution with no evidence of layering, stepping or pitted surface finish. The loco bogie sides I acquired were FUD and were every bit as fine as bachmann IMP ones. Strangly after layers of priming, painting and varnishing it's difficult to see much difference between resin models and 3D WSF/WSFP. FUD is too expensive right now, but for a unique model body (e.g. Mk4 DVT, A class) it might be worth the cost, and if costs ever come down in the future I wonder if 3D may end up having a role replacing resin and in some cases even brass components or some etches?
I may be interesting in five years time, to look back and see if and how many non-mainstream Irish models may or may not be available as 3D models (presume kit form) ready for painting by markets such as Shapeways, or DIY modellers using various print service providers. For modellers It could be a game changer, or an empemeral technolgy.
Cheers
Noel