James Harrison Posted March 23, 2013 Share Posted March 23, 2013 This is hopefully going to be my first foray into 3D printing. There's a heck of a long way to go yet just to get the drawing sorted! I'm hoping to draw up a 3D model of a LNER B5/1 [GCR class 8 ]. I've never really managed to grasp 3D CAD draughting despite my architectural background and indeed tried four different programmes yesterday afternoon only to end up in a complete muddle with each one in turn. A more considered approach last night in AutoCAD 2013 did render a little positive result and a half hour this morning improved upon that. I started out with a set of 7mm drawings of the loco in an old copy of Model Railway News and a 4mm profile in a portfolio of Charles Reddy drawings, so I'm slowly transferring these across into AutoCAD at 4mm scale. As you can see at the moment I have only the splashers and the footplate as far back as the cab, but I'm hoping by this afternoon to have at least a full running plate and cab sheets done too. I only have the 30-day trial of AutoCAD so the pressure is on to get the drawing done to the point where I can export it before the trial runs out! My plan at the moment is to draught out a basic body- running plate, splashers, cab and boiler- design it to fit onto a Hornby B12 chassis (which will need re-wheeling) and use cast whitemetal or brass components for the boiler fittings. Link to post Share on other sites More sharing options...
James Harrison Posted March 23, 2013 Author Share Posted March 23, 2013 I struggled on for a little while and then started to get frustrated with lines and components snapping to completely the wrong location. Clearly a re-think was in order. What I there did was to import my MRN 7mm drawings into CAD as raster images, and then start tracing over them. The idea is that I trace each component, extrude it to a half-model, and then drop it onto a new 3D model taking shape below the original drawing. So far it seems to be yielding results! Link to post Share on other sites More sharing options...
James Harrison Posted March 23, 2013 Author Share Posted March 23, 2013 I reckon this is good, for an afternoon's work.... Now what I have to do is figure out how to carve away the unwanted/excess material. I might try exporting into sketchup for this bit.... Link to post Share on other sites More sharing options...
Guest Phil Posted March 23, 2013 Share Posted March 23, 2013 Very impressed with your work James. 3D printing is certainly a very useful medium for railway modellers, especially of obscure types like yours, which I had never heard of !!! Really hope you achieve your target (30 day challenge) and please tell us after you have finished a great deal more about the project. Link to post Share on other sites More sharing options...
backofanenvelope Posted March 24, 2013 Share Posted March 24, 2013 As the person that initiated the group and having sadly not actually created anything of note yet I applaud your efforts. A very good start and I am sure you will make a good go of it. There are plenty of free programs on offer for when your Autocad expires in fact there are some good autodesk alternatives. I am looking forward to your progress. Tom. Link to post Share on other sites More sharing options...
James Harrison Posted March 24, 2013 Author Share Posted March 24, 2013 Thanks for the encouragement! Today's task I think will be to try to create the same model in Sketchup, as I've found that the trial version of AutoCAD does not want to export drawings in a format which is actually useable anywhere else. Ah well- it's been useful experience and helped get me back up to speed with the programme after a gap of three years. More to show later no doubt! Link to post Share on other sites More sharing options...
James Harrison Posted March 24, 2013 Author Share Posted March 24, 2013 I'm finding sketchup easier to draught in, though it's not quite so intuitive as AutoCAD. That said I have already managed to create a more complex running plate than I did yesterday... that in CAD was a simple rectangular block whilst this one has the requisite cut outs to fit over a chassis. I'm continuing my method of producing a half-model and then copy/mirroring it. Link to post Share on other sites More sharing options...
James Harrison Posted March 24, 2013 Author Share Posted March 24, 2013 Getting there... it's a bit of a struggle but I'm getting a better result than I did with AutoCAD yesterday.... Link to post Share on other sites More sharing options...
James Harrison Posted March 30, 2013 Author Share Posted March 30, 2013 I'm pleased to say that I think I might just be in a position to get it sent to Shapeways for a quote.... to cut down the cost I'm planning to just get the basic loco body 3D printed; I was already planning to use whitemetal or brass castings for the boiler fittings and buffers and a tender should be an easy enough proposition to do 'as usual' in plastic sheet. Link to post Share on other sites More sharing options...
James Harrison Posted March 30, 2013 Author Share Posted March 30, 2013 Good news: I could have printed the model straight off the bat.... bad news was that for some reason the cab was mussed up. It took about 5 attempts to get the cab roof right and then bring the model down to scale, and even now I'll have to add a cab front from plastic sheet.... But it's sorted now and with Shapeways for printing. This is what I'm getting: When I get it built and working I may put the basic shell up for sale, if anyone's interested. Link to post Share on other sites More sharing options...
cheesysmith Posted April 2, 2013 Share Posted April 2, 2013 Looking at the 25 cabs thread on this 3d section, could you not copy his idea from the tankers and miss the boilier out and use a piece of pipe of the right diameter? That would make it even cheaper way to print the paralel boiler locos and overcome the stepping you get trying to make cylinders. Link to post Share on other sites More sharing options...
Marbelup Posted April 2, 2013 Share Posted April 2, 2013 Question - do the facets on the cylindrical surfaces appear on the STL file or are they an artefact of the on-screen rendering in Sketchup? If you are still in the trial stage, you might want to consider Rhino 5 which is available for 90-day free evaluation, fully functional. (http://www.rhino3d.com/download/rhino/5.0/evaluationtimed) I have been using it for about 6 months now. It is a bit expensive to buy but there is an educational version if you qualify for that. Like any software, it has a few quirks, but is is very precise (down to 0.001 mm) and it doesn't take long to get the hang of it if you are used to 2D CAD. I have used Autosketch for many years and the basic drawing features felt like a logical extension of what I was doing in Autosketch. Rhino tends to generate a few tiny glitches in the STL file but I routinely check and fix the STL's using NerFabb Cloud service prior to submitting to the online print service, and I haven't had any problems with file errors or rejections once submitted. For my latest project, I am getting carried away doing detailed brake rigging for a 4-wheel sheep wagon (in S scale). Rhino is certainly capable of drawing fine details, and I am working in model scale, not drawing larger to scale down later. Link to post Share on other sites More sharing options...
SpoorObjecten Posted April 2, 2013 Share Posted April 2, 2013 The missing pieces are caused by overlapping faces. Have a look at this topic for more information and solution: http://www.shapeways.com/forum/index.php?t=msg&th=6780&start=0& The non-smooth shape of the model is caused bu the number of steps used in your circle. In your sketchup picture you can see that you are not using a lot of faces (see the black lines) The more polygons you use, the smoother the model will be when printed. good luck! Link to post Share on other sites More sharing options...
James Harrison Posted April 2, 2013 Author Share Posted April 2, 2013 I'm not entirely sure concerning the facetted nature of the boiler- it could be a relic from using Sketchup, or the model could turn up like that :/ In hindsight it would have been better to use a piece of plastic pipe for the boiler, but as I tend to struggle to get the shape of the firebox right I'd have been in a mess either way. Hey ho, if railway modelling was always easy I doubt I'd find it enjoyable! Link to post Share on other sites More sharing options...
Rabs Posted April 3, 2013 Share Posted April 3, 2013 The non-smooth shape of the model is caused bu the number of steps used in your circle. In your sketchup picture you can see that you are not using a lot of faces (see the black lines) This is true. Your model will very probably come out as a polygon rather than a cylinder - because that's what the model shows with the dotted lines. Sketchup's default circles are quite low edge/polygon count. Whether this is good or bad depends on what you are trying to do - it's good for computer graphics but bad for 3d printing. Just because it looks round doesn't mean that it is in Sketchup. If you are doing it again then you can try the following trick: When you select the circle tool (also works for the arc tool) but before you click to place the centre of the circle have a look in the bottom right of your screen. There will be a number box called 'sides'. You can press tab and enter a lager number here. You have to do this before you click to place the circle, because this box becomes the radius value at that point. Hope that that helps Link to post Share on other sites More sharing options...
James Harrison Posted April 3, 2013 Author Share Posted April 3, 2013 That is a very useful tip thanks! I'm hopeful it won't be 'too bad'.... I'll get the boiler in the round with some milliput, but if there's too much work involved I suspect I'll cut it away and use plastic conduit pipe instead. Apparently I'll be getting my print sometime around the middle of April; I can't wait! Link to post Share on other sites More sharing options...
cheesysmith Posted April 4, 2013 Share Posted April 4, 2013 nother reason to sugest it was doing the pipe for the boiler would cut down on the printing cost. They do charge by volume, and the actual boiler would be the biggest piece. Link to post Share on other sites More sharing options...
Rabs Posted April 4, 2013 Share Posted April 4, 2013 Indeed - it's a pity I model GWR so can't make use of that cost-saver! I, of course, meant a 'larger' number. A lager number probably wouldn't be all that useful! There's nothing to stop you cutting it out and putting tube in after you get the model if it isn't up to scratch. Alternatively you could skin it with a thin sheet of brass or plasticard. Anyway, as you say - best wait and see how it turns out, it might be perfect as it is. Link to post Share on other sites More sharing options...
James Harrison Posted April 5, 2013 Author Share Posted April 5, 2013 I think the first thing I'll try will be to cut a plastic former and pull some milliput along the boiler barrel. If that doesn't work I have in the past been able to roll thin paper to make boiler wrappers. If that still doesn't work the I think only thing left to do will be to replace the boiler barrel with plastic conduit. It should be an interesting little project at any rate. Link to post Share on other sites More sharing options...
James Harrison Posted April 10, 2013 Author Share Posted April 10, 2013 IT'S ARRIVED!!! I got home from work today to find a package waiting for me.... opening the box revealed this inside.... I went with Shapeways and their white flexible material. There's no exceptionally fine detail on the model so it seemed extravagant and pointless to go with FUD. Comparing it with a drawing of the model (I was a little worried about how it would scale out!), it's darn near perfect. The smokebox is a little short but that's about it.... The boiler has come out as a series of flats but they aren't particularly severe; a bit of shaped plastic with some milliput smeared on it would round the boiler out in no time. Very happy with this! Link to post Share on other sites More sharing options...
Marbelup Posted April 10, 2013 Share Posted April 10, 2013 If it was me, I would be trying to get the round shapes right before printing. I am sure SketchUp is capable of better as Rabs has suggested. It is still pretty amazing to get the printed shape back based on the design you have created on your computer. Link to post Share on other sites More sharing options...
cheesysmith Posted April 12, 2013 Share Posted April 12, 2013 You now need to keep us updated on how this goes on. Be interesting to watch. Link to post Share on other sites More sharing options...
James Harrison Posted April 12, 2013 Author Share Posted April 12, 2013 I'll be sure to post updates... it's going to be the next loco on my workbench (I'm currently working on a whitemetal D11). Link to post Share on other sites More sharing options...
James Harrison Posted June 1, 2013 Author Share Posted June 1, 2013 Progress report... I've got the chassis sorted out finally (the trials and tribulations of that I'm not going to go through here- suffice is to say it put up a struggle), and then started work on the body. I had to start by working away at the bits which had been printed more for convenience of the drawing than the model itself- for instance, on the insides of the splashers where the firebox intruded into the space for the wheels. It was difficult to do this by hand as the material I'm finding is quite difficult to work, but with a dremel it was the work of a minute or two. I drilled a couple of holes into the bottom of the running plate under the smokebox, to allow a couple of screws to hold the body on the chassis and also hold the cylinder block in place. I then drilled a pair of holes on the boiler barrel to fit the chimney and dome in place. I gave the boiler barrel a coat of white putty, and then sanded it down to remove the angular appearance, then painted it matt black and repeated the exercise. At the moment then the model looks like this I think that the cab roof is to the wrong profile, so I'm planning to replace it. Link to post Share on other sites More sharing options...
James Harrison Posted June 2, 2013 Author Share Posted June 2, 2013 I cut off the cab roof, then straightened it out a little, rolled it on a scalpel handle to get a smooth curve, and glued it back on (after I had added a spectacle plate in slivers of plastic sheet). I've paired it up with a Triang tender off of an L1 or 2P.... this will also need to go under the knife at some point to get it looking GCR/ Robinson-like. Link to post Share on other sites More sharing options...
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