Adventures in 3D CAD

[Bedders]

I've got to the stage where I'm either gong to have to share my dabbling with the world or forever be a reader rather than a doer   I hope you can see the progresson towards a higher quality of work.  I've found I can make good progress with openSCAD as I have a computer programming background.
 
I started off with pillboxes, the geometic shapes and straight lines appealed as a starting point.
 

 

I then moved on to the curvy delights of the Nissen Hut, followed by the standard LNER concrete platelayers hut

 

 

I'm moving on now to a GCR Barnum coach, I don't have accurate drawings as of yet, but the parametric nature of openSCAD should allow me to tweak my measurements when I can lay my hands on some.  I'll be following this up with an MSLR tri-composite

 

 

 

 

Edited March 25, 2015 by Bedders

[Bedders]

Barnum coach so far

 

[Etched Pixels]

There are some basic dimensioned drawings of the Barnum and a few other GCR vehicles in Historic Carriage Drawings in 4mm Scale Vol.1. They are not bad but contain the odd error that can be checked against photographs. There are also some handy diagrams in vol 3 in particular of Dow  'Great Central'

 

I've been doing some of the GCR coaches in N in part from these drawings and they are certainly adequate if not perfection.

 

Alan

[Bedders]

Thanks for the steer Alan, the historic carriage drawing book has been on my radar for a while in general terms, I need to sort out my domestic arrangements and rejoin a library.  I didn't know the Dow series had drawings in it, I'll have to see if I can borrow that as well 

 

Current progress on the MSLR Tri-Composite, getting the beading to match the curve of the tumblehome was an interesting mental challenge in openSCAD

 

 

[Etched Pixels]

If you don't mind the beading edges being a tiny shade off the normal with the side (and imperceptably so IMHO) then the approximation is to make the side and the panels both solid blocks and then intersect them with the tumblehome profile at different positions. Rather easier than computing the normals and works fine for shall curves like sides, but not such a good idea for roof detail ! You need to make your sides a flat projection if you do this - if you start with a side designed to be curved and then extrude and intersect you of course end up with the positions somewhat wrong.

 

The Dow book (vol.3 for the most part) has basic diagrams of the various coach types showing all the window layout and other handy details for each type. Historic Carriage Drawings has better detail but covers only a few vehicles - Barnums and the later stock, none of the six wheelers or shorter stock. In fact I've not found a good book on GC rolling stock at all.

 

Alan

[Bedders]

Thanks for the advice, it's always interesting to hear how other people approach similar problems.  Part of the fun for me is putting the thought into getting the details right, my day job just doesn't give me that sort of problem to get my teeth into and I can take as long as I want with it.  Basically it's me making it difficult for myself

[Beatty 139]

There are some good (works or period) construction drawings for the Barnums in David Jacksons book J.G.Robinson a lifetimes work published by oakwood press.

 

Could I ask where you found your drawing for the LNER platelayers hut I have been looking for one for a while and I am still looking for the LNWR Webb Huts drawings.

 

Thanks

Andy

[Bedders]

I got the drawing from Model Railways, March 1975, via the very kind Mick Nicholson on the LNER email list.  If you don't have access to the magazine either, PM me your email address and I'll send you the scan.

 

Thanks for yet another book reference, I might have to start getting these out the library and creating an index for GCR resources.

Edited April 21, 2013 by Bedders

[Bedders]

 

Futher progress on the Tri-composite body, need to get up to the KWVR to take some photos of the details and underframe before I can be completely happy with it. 

[Beatty 139]

if your in the midlands Chasewater has a MS&L 6W its not been messed about too much below the solebars and could be closer than the K&WVR.

[Bedders]

Thread resurrection time! With little fanfare I give you... Partially finished GCR 9F/LNER N5.  There is a fair bit of work to do on the frames but the list of jobs for above the line is getting quite short now.

 

[JCL]

Hi there, are you still on OpenSCAD or have you moved onto something else?

 

Oh, and how did you get on with the Barnum? If you are still looking at it, I managed to get into the shed where a couple are being stored. It was quite tight, but I managed to get some photos of a fashion - no complete side I'm afraid, but a lot of details. There are 4 albums (Barnum 1-4) here if they are of interest: https://www.flickr.com/photos/127184510@N04/sets

[Bedders]

HI, still working in OpenSCAD as it suits the way I think with my background n programming.  I've enjoyed your Blender tutorials though and might be tempted to use it for some parts in the future if they have complex curves. Inspired by the chassis Brack made for his Y7 -  and AJ for his J50 and the price I'd have to pay for a Bachmann 3F as a donor, I'm going to have a go as printing my own, Talk about leaping in with both feet  I've ordered the motor and gears to force myself to actually finish something and a very small improvement in my finances is helping too.

 

 

The Barnum is on the back burner, but I might restart it after the N5.  I've seen the photos and it's good to have some close ups to work with.

 

What size and shape did you end up printing the rivets on your single and D3?

[Bedders]

Works continues, snag list reduced to a few more rivets, cab internals and roof, possible bunker flare, buffers, safety valves, steps, a few more handrail holes and a hint of inside motion.

 

Edited April 20, 2015 by Bedders

[JCL]

Sorry Bedders, I'd missed your update after mine. It's coming along really well. I was working in 4mm scale and the rivets were balls/orbs/globes at .45mm diameter. That said, I was thinking of changing this to a cylinder of the same diameter with chamfered edges that stands a little more proud of the surface so that it can withstand a bit of abuse from the sanding process.

 

I am incredibly interested in how you will get on creating your chases as, although they exist on shapeways, I haven't read about anyone's experience with how it came out yet. There's no reason why it can't be done. Are you using shapeways, and if you are, what material are you thinking of?

[Bedders]

No worries, thanks for the information.  I'm just trying to get as much right as I can before I send anything off to print.  I have to be very careful I don't procrastinate too much and not finish stuff off...

 

The chassis will be in FUD, the same as the body.  From what I've read it is more hard wearing and dimensionally accurate than WSF, though I will be using brass axle bushes.  The design will be based on Brack's Y7, though I need a bit of a re-jig as the motor I ordered has turned out to be smaller than I thought!  I'm a bit worried about getting the bevel gears aligned and keeping them so - I guess the secret will be to not have any side-play on the drive axle.

[Revolution Mike]

The chassis will be in FUD, the same as the body.  From what I've read it is more hard wearing and dimensionally accurate than WSF, though I will be using brass axle bushes.

 

Hi Bedders

 

Where did you hear that from? I doubt very much that FUD is more hard wearing than WSF - WSF is essentially sintered nylon (IIRC) and very hard wearing (and difficult to file!).

 

Cheers, Mike

[Bedders]

I've had a quick look at my bookmarks and I can't find reference to the wearing properties, so I'll defer to you on this The accuracy is better though and I think that will help to make a working chassis. ± 0.025 - 0.05 mm for every 25.40 mm versus ± 0.15 mm, then ± 0.15 % of longest axis

[JCL]

It'll be interesting to see how you get on. I've had my replacement GNR A5 delivered, so now I have two bodyshells and one Hornby Caley 123 chassis so I'm mulling over testing a chassis in WSF.

[Bedders]

I'll keep the updates coming, but the speed you work at, you'll have one before me.  It would be worth canvassing the 2 chaps mentioned in post #13 as they have already produced their chassis

[Bedders]

 

Blimey, it's been nearly a year since I posed anything here!

 

Thought I'd better show some of my working, so here's a GCR 6w 3rd.  I'm going to see if I can make a Cleminson chassis work, nothing like being over ambitious.  Couple of details to add before I'm completely happy.

 

[Bedders]

What's 5 years between friends or, indeed, posts?

 

First proper prints on my Elegoo Mars, the centre 3rd of what will hopefully be a GCR dining 1st. Droopy corner at the bottom left needs an extra support, but apart from that a vindication of printing it vertically with supports only on the end. Second picture IPA bath and UV cure only.

 

[JCL]

Nice! I have to say, cutting the Shapeways cord was a good move for me, especially up here in Canada.

[Bedders]

Shapeways changing it's pricing structure, usually up, did for me. The printer pays for itself in a handful of prints

 

Changes for v2 will be continuous supports to give a crisper edge and and to hide the vestibule join up inside the roof. Not entirely happy with the clerestory windows. I like the shape of them being open, but will be a pain to glaze if  I put a hole in them

Edited March 25, 2021 by Bedders

[JCL]

Well they look like they are fitting together pretty well, it'll be interesting to see your v2 and how crisp you can get your edges.