¡Hola! The 3-Foot 6 DM Class - 1

DB puedo hablar un poco de español:

Despite having one of these prints on my bench for some months now, it seems I'm going to struggle to get it into service before the real thing. 

Initial thoughts on the print: 

It looks waaaay overscale when placed next to my model DXCs - too tall and too long. It seems it's not, the real thing being a lot bigger than we are used to! 

Great detail - the difficult cabs and front end are well represented, even the front handrails are there. The roof details are pretty good too, although some are quite subtle and may vanish under a coat of paint. 

Further investigation:

After the real DMs arrived here and were seen in the flesh, it appeared like they would be a very challenging prototype to model. The sides are very detailed, and the prominent black rubber joins between the door panels will be really hard to paint and imagine applying the decals around these. 

There are also differences between the shell and prototype in the side door panels, especially those close to the cab, and on one side of the loco (the 'upside down' side in the image below) which has the square dynamic brake inlets. Not that many people would notice any of this. 

So I decided straight away that my sides would be photo overlays printed onto glossy paper, a la Ken Devlin Specials.  I spent about three hours one night building up the sides from photographs. This required perspective correction, scaling, colour matching, and - for the other 2.9 hours - removing the complex side handrails from the photos.

If anyone wants this full size (about 4000x4000 pixels) you can email me at the LinesiderNZ email. Maybe Lewis might host it on his website as this will get compressed. 

I took the file down to the print shop, printing it on the same paper The Linesider uses. The first page looked too magenta, so a little green was added, and by the third copy it looked about right. Even if you take the same file to three proper commercial printers, you will likely get three subtly different hues depending on what paper, ink and model of printer is being used, and the temperature, humidity and even whether the printer is warmed up or not will affect tones, which are basically dependant on how the different colours of ink (cyan, magenta, yellow and black, or sometimes red, green, blue) are absorbed into, and layer up on, the paper. The things I've learned over the past few years.

With this done and laid over the top, it made obvious a few shell issues which will likely be corrected in a future iteration of the 3D model. Primarily that the radiator section (roof fans and 'union jack' sides) is a bit close to the cab at that end. This also pulls the adjoining chunky roof section over the engine/SCR unit  (with its four 'feet') a bit further off-centre. 

On the side sills, the circular lifting lug holes are also slightly misplaced. This is what made me initially wonder whether the shell was overscale, because the bogie centre spacing was one of the few prototype measurements I had when the shell arrived. I'm not sure I will remember to move them...

The panel-side details aren't going to be a problem, as I'm going to be using my paper overlays anyway, but I will need to move the roof fans to sit over my union jacks, and this will require moving the engine room roof as well. I'm also tempted to make the roof a/c units more prominent, which will make them easier to paint.

Into Surgery:

The first thing I decided to tackle was to slightly alter the cab roof top corners. These are angled (as modelled on the shell) at the 'back' corners to give plenty of door height access into the cab, but at the front, the real thing transitions to a more rounded shape. A little filing sorted this.

When viewed from above, the front face of the cab should also curve a little more at the corners, rather than having a bevelled join. I had a little crack at this, but not in the top-right corners (when viewed from the front) where there are a nice handrails printed. 

The 'cowcatchers' were also subtly modified at the bottom. There's not much to fault though, as the very complex cabs have been modelled well.

After the pic above was taken, I also opened out the bottom of the coupler pocket to take MicroTrains couplers - another message to designers - every 3D printed coupler box I've ever seen has needed to be enlarged.

The roof fans and engine lid were moved about 5mm towards the middle (I was also able to move my sides slightly the other way to meet them!).

So in summary, you could well say none of this surgery really made that much difference. 

And below, with filler added, ready for painting. 

First few coats badly sprayed: