3d modelling - Irish Narrow Gauge (and ZRR 15th class garratt)

[ben racey]

Hi Geoff,

Thanks for the links, both are most interesting. The first one is more how I've previously approached these things!

 

Regards

 

Richard.

 

 

[tebee]

Going back to the Thing-o-matic I finally found a review of it here http://www.prestonlee.com/2011/01/18/makerbot-thing-o-matic-3d-printer-print-pictures-product-review/ and I don't think I'll be rushing out to buy one.

[Hobby]

This is the second Mk48 I bought from Shapeways... On the first I tried all sorts of methods to get rid of the "texture" but with no good result, except loss of detail. This one was just painted with three coats of Humbrol Satin Enamal. Whilst its not ideal its worth pointing out that the photo comes out as larger than life on my screen, and in reality, viewed from normal distance, it looks ok. Chassis is from Atlas.

 

[ben racey]

Thought I'd post up a couple of photos of an engine I've made using the shapeways technology, it's not narrow gauge, but I think shows that the texture issue with the white strong and flexible can be overcome.

 

The chassis is from the white detail material, quite thick to give it strength, the body is white strong and flexible. I've used plasticard (10 thou) superglued on for the rivet detail. Fixtures and fittings are a mixture of bits box brass and whitemetal. Wheels are Romford and coupling rods are Alan Gibson variable length connecting rods. I designed a small jig at the right spacing to make up the coupling rods to the right lengths.

 

Regards

 

Richard.

[invercloy]

Without wishing to sound rude, the surface finish looks a lot better than I expected on that, Ben. I was dubious about how much changing the parameters used by Shapeways would improve the finish. Have you done anything to this to smooth it off some more?

 

What software do you use to design your stuff?

[ben racey]

Hi Tom,

 

No rudeness implied or received at all!

 

To get the smooth surface finish, and the surface detail, I've used 10 thou' plasticard, embossed the rivet detail on the rear and glued on with superglue, rather than liquid poly so that I don't get any distortion. This applies to the chassis which is White Detail, and the body which is white strong and flexible. This then gives you the nice smooth finish - the textured finish of the WSF material helps the process as it helps the glue key nicely.

 

I'm using Google Sketchup to design my models, then processing using Netfabb Cloud and or Cadspan / Cadspan Pro. It's fairly straightforward to use Google Sketchup I think, though the processing to make the models suitable to print is a little tricky to learn at first.

 

Regards

 

Richard.

[invercloy]

I didn't realise you could use sketchup, fantastic! I'll have a look into Netfabb Cloud too. Thanks for the tips, inspiration to do my own!

[Patrick]

Thought I'd post up a couple of photos of an engine I've made using the shapeways technology, it's not narrow gauge, but I think shows that the texture issue with the white strong and flexible can be overcome.

 

The chassis is from the white detail material, quite thick to give it strength, the body is white strong and flexible. I've used plasticard (10 thou) superglued on for the rivet detail. Fixtures and fittings are a mixture of bits box brass and whitemetal. Wheels are Romford and coupling rods are Alan Gibson variable length connecting rods. I designed a small jig at the right spacing to make up the coupling rods to the right lengths.

 

Regards

 

Richard.

 

 

Am I seeing things or is that a Bandon tank? Looks excellent...

[ben racey]

Yes, it is a CBSCR Bandon Tank, glad you like it!

 

 

[Patrick]

Yes, it is a CBSCR Bandon Tank, glad you like it!

 

 

 

 

Good to know my Specsavers glasses are working properly! Studio Scale Models recently released an etched kit for the Bandon Tank, in case you're interested.

 

Now, I'll stop digressing and let you get back on topic...

[ben racey]

Hi Patrick,

 

Yes, I was aware SSM are doing one - I was planning to do mine as a kit on shapeways, but now SSM have done an etched kit, I don't want to release it as a kit. Though I may do the odd one ready to run in 16.5mm. I'm planning a GNRi JT tank in due course though....

 

I've also made some progress on the garratt, I'm keeping the shapeway bits simple, just the major bits boiler, frame, cab and I will add details including pipework, chimney dome etc from cast brass parts. The 15th class seems to have had an almost infinite amount of detail differences over the years! Link to the boiler unit here:

 

http://www.shapeways...tml?gid=sg32411

 

and the rear tank here:

 

http://www.shapeways...tml?gid=sg32411

 

Regards

 

Richard.

[ben racey]

Hi all,

 

A bit more progress on the Garratt project. The attachments show a few screenshots from Sketchup of the design. I've started by drawing out the rails, wheelbase with wheels on one side. Then designed the chassis 'in place' as it were. As I've drawn the wheels on one side, I can draw in the valve gear using the correct dimensions. Then I've used the measuring tool to draw out the supports for the rear tank inside the water and under the coal spaces. That way I can keep the nuts and bolts out of the way. The detail shots show the driving frame and the underside of the rear tank.

 

As I've gone along I've drawn out the front tank, boiler cradle, and rear tank in alignment to check the alignment and how it looks from the dimensions measured from the MOSI drawings. As you can see it's pretty broad brush as I intend to add all the details once it arrives - also can't draw compound curves yet using sketchup, so I'll have a bit of sanding to do when it arrives! There's so many detail differences, not withstanding things such as shape of the rear tank!, to place and location of lamps, pipes etc, should be fun trying to get it right!

 

Cheers for now.

 

Richard.

[Ohmisterporter]

It looks good on the drawing Richard. Also very simple but we know how deceptive that can be. On the front tank where you have left the corners on to be sanded off later, how much wall thickness have you allowed? I am wondering how different thicknesses affect the process with regard to distortion? I worked in the plastic injection moulding business and I know that what we call sinking can be a problem in thick areas.

I'm enjoying this project and wish you well with it.

 

Geoff.

[ben racey]

Hi Geoff,

We shall see when I receive it. I'm not a trained 3d developer, so am learning as I go. But so far I've had one of the swilly coaches since september, with no movement detected. Others have seen evidence of warping if designing walls that are too thin for the white detail material - I've tried to alleviate this with the chassis and tanks by building in small 'lips' at the bottom of the tanks and chassis to give a bit of extra unobtrusive strength. I've not seen a problem with 'too thick areas', other than the extra cost! It'd be nice to do the chassis in the steel material, but at present the wall thickness is too thick for our requirements.

 

Thanks, glad you're enjoying following my efforts on this.

 

Regards

 

Richard.

[backofanenvelope]

Hi Ben

 

You may fine this site useful? http://sketchucation.com/

 

t.

[ben racey]

Hi, Thanks for the link, looks really useful, I've bookmarked it!

 

Regards

 

Richard.

[Tricky-CRS]

Ben looking good.

[dajt]

Good job on the coach. It's nice to see people experimenting with new techniques.

 

Regards,

David.

[ben racey]

Woo! Just got the nod from Shapeways thast my garratt prints are on the way! Hopefully will be in tomorrow, will post up some pictures when it arrives!

 

Regards

 

Richard.

[ben racey]

Hi All,

Got the 3 body prints yesterday, the chassis are on the way but have been dispatched separately as they are made from a separate material. Will post further piccies when they arrive. So far though, really pleased with the look of these, I've perched the front tank on my prototype chassis to try and get a feel for the thing as well. The curve issue on the front tank isn't as much of a problem as I had feared, a few strokes of the file should sort. The boiler cradle unit also looks well, there is some cab detail in there as well, regulator, firehole door. The roof is connected with some sprues to the body so that it can be removed for painting etc.

 

Anyhow, that's it for now, really looking forward to getting the chassis prints.....

 

Regards

 

Richard.

[ben racey]

Hi All,

 

A few photos of the engine now that the chassis units have arrived.... parked up on my Polish layout for no particular reason!

 

Something just isn't right about the way the engine looks though, whether it's because the boiler is too low in the cradle, or the front tank is too low, I'm not sure... These engines are so large they tend to be photographed from the trackside, hence the angle of photos is from the ground rather than above as with model photographs..

 

Still thinking about how I'll develop this one, views welcome!

 

Regards

 

Richard.

[ravenforth]

Hello Richard, great work on that Garratt. I've been admiring your designs recently. Really top drawer, and good work on the Shapeways forum for articulating the needs of railway related designers.

 

Just a question about the boiler curvature - did you use a higher "segmentation" number in Sketchup, that didn't transfer to the Shapeways print out, or are the slight ridges by design? I'm getting to a point with my Shapeways designs that the curvature values will be relevant with boilers and chimneys. The default is 24 segments per circle, but it's a pain to remember to change it first to value like 96 or 192 before drawing the circle and extruding!

 

Jamie

[ben racey]

Hi Jamie, and thank you for your kind words, much appreciated!

 

I didn't change the segmentation in sketchup - haven't got to that stage with the designs.... Though I haven't been too worried yet as I plan to use a plasticard overlay to the boiler when eventually happy with it! I've only recently braved the world of chimneys and domes with my PX48 design. Still very much learning!

 

Regards

 

richard.

[Grovenor]

Something just isn't right about the way the engine looks though, whether it's because the boiler is too low in the cradle, or the front tank is too low, I'm not sure...

If you have allowed for a layer of plasticard over the boiler that might explain it, as, to me it looks a bit slim, the Garratt boilers were generally short and fat. There were at least 3 types of front tanks used on the 15s so you do need to compare with photos of the right one, they got bigger over time.

Its looking really good to me, could a print be made in 4mm scale?

Regards

Keith

[Grovenor]

Comparing to my photos "Here"I would say front tank is OK relative to boiler but boiler looks a tad low relative to cab roof, which that plasticard layer might fix.

Regards

Keith