16 Ton Mineral and LNWR 0-8-0

[44767]

A while ago I started to model in 3D this mineral wagon. It is not yet finished but very nearly. The programme I used is Alibre and is a parametric 3D modelling programme similar to SolidWorks but not as comprehensive and therefore not as expensive. The model is based on drawings by Doug Hewson.





Similarly I am modelling "Wessie". I started off keeping up with the articles in EIM but have slipped behind a bit recently.



This is a great way to find out if there are any errors on the drawings or to measure things which aren't dimensioned on the 2D drawings.

[kingsteam9]

Mike,

Very impressive! How easy was it to learn to use Alibre?

Robin

[drjohn]

Feb 5, 2009 12:17:26 GMT 44767 said:

This is a great way to find out if there are any errors on the drawings or to measure things which aren't dimensioned on the 2D drawings.

Is it not easier just to look at the drawings and do the calculations on a calculator?

DJ

P.S. Where in Auckland are you - I have a brother-in-law in Devonport

[davediy]

hi
nicely done just wish we had a zoom facility for pictures on this forum.
Is the program you use anything like goggle sketch-up as this is the only program I have experience with so far
dave

[havoc]

Looks fun. I'm going to check out Alibre. I'm quite familiar with Solidworks and if it is similar and sufficient for amateur use like what we do then this could be a good alternative.

Only issue with such cad excercises is that they end up in feature creep. After the basic things you end up with evenings drawing invisible features. Not because you need to but because you can.

Is it not easier just to look at the drawings and do the calculations on a calculator?

Not always. I'm converting Netta (gauge 1) to metric in solidworks. Started with just calculating everything and using the same dimensions. Some things don't work out. Like the hole for the cilinders in the frame has contradictory dimensions. 3D let you catch this easily. Same for missing holes, once you start assembling components you find them fast.

[44767]

Robin, Alibre is really quite simple. One draws a 2D drawing as you would in AutoCAD or whatever and once the sketch is done it is used to create a "solid" feature by extruding, cutting, revolving, lofting (solid between two or more sketches) etc. If you then want to change a dimension then just alter the dimension in the sketch and everything that was constrained to it updates with the change.

Once you have a part it can be mated in an assembly. This is where it is really useful for checking if things line up. Drawings are automatic and cross sections are a doddle.

In answer to your question, it will take a bit of time to get a grip of it but they have very good tutorials and, as long as you keep up the maintenance, very good on line help and a user forum just like this.

It was set up for those who could not justify the cost of SolidWorks. When I bought Alibre it was about NZ$2000; SolidWorks is about NZ$13 000 and NZ$3000 per year maintenance! Consequently it lacks some of the tools that SW has and so if you've used SW you'll probably get a bit frustrated.Still very good for what we do. You can save models in all the formats e.g. STL and STEP, IGES etc. At the time I bought it it came with a basic version of VisualMill. This is a CAM package that I use. I ended up buying the full version and because I had Alibre, I received a 20% discount off the price.

DJ, Much better than working it out with a calculator. With a calculator you have to know what you're looking for; this way everything stands out at once. You can then edit a part "in context" e,g, move a hole to line up with one in another part and it's all done, the drawing changes automatically, too.

I live in Mt Wellington, close to the ASME track.

Dave, I don't know what Goggle Sketchup is at all!

Havoc, Did you know that you don't have to calculate the metric equivalents on SW? You just type in the imperial measurement with "in" straight after it and it does it for you. No errors then!

[44767]

I have just increased the size of the pictures. These are only screen dumps so anything much bigger will start loosing clarity.

[simonwass]

I like those a lot, the realism is amazing.
Its taken me a few years to get reasonably good at just technical drawing with Acad2000 so I can see 3d modelling being difficult to learn as a diy task? I havent even looked into Acad2000s ability to do 3d sketches yet but I would love to be able to draw a part and then 'look around it'!

[drjohn]

It's interesting how the lack of perspective makes the rear wheel on the second picture look wrong - but then for plans, that's not the point.

Incidentally Mike, your pictures of the Black 5 in "My George" seem to have disappeared?? Or is it just my internet service depriver playing 5th world country again? ;D

DJ

[kingsteam9]

Mike,

Thanks for the insight on Alibre - I'll have to try it; I've seen it mentioned by Nemett in M.E. before. I'm not familiar with Solidworks but use AutoCad for work/hobby and a 3D package would be a very useful development.

Robin

[havoc]

Havoc, Did you know that you don't have to calculate the metric equivalents on SW? You just type in the imperial measurement with "in" straight after it and it does it for you. No errors then!

I'm using 25.6mm for an inch, that gives nicer numbers ;D This mean that apart from screwholes, axles, rivets, balls etc I don't have to change any dimensions later. As an example, take a length that is 5/32". That would be 3.969mm if I take an inch as 25.4mm But it comes at 4.000mm if I use 25.6 as an inch. Same for 7/16", that becomes 11.2mm instead of 11.112mm. And as the original plans are in fractional inches (and at places hardly readable) it goes about as fast.

Its taken me a few years to get reasonably good at just technical drawing with Acad2000 so I can see 3d modelling being difficult to learn as a diy task?

I can't speak for Alibre, but it takes about a week to get started on Solidworks. A few months regular use to get the hang of it.

Time actually spend on modelling something like an engine depends on how anal you are

[44767]

The pictures of George are still up as far as I can see.

Those are perspective images; the one below is from the same sort of angle but is not perspective.



The trick to getting to look so real is that all the parts have very small fillets on the edges. This makes the light play off it in a much better way.

I wouldn't say this is an anal thing to do Havoc. Practise makes perfect. What better thing to practise on than a loco that has only been drawn by hand? One day someone may want this information. I have already redrawn the rods as in EIM they looked nothing like the full size and the forked joints in the coupling rods were around the wrong way.



Which lead to these:



www.flickr.com/photos/mkrj/3259354016/

[simonwass]

Feb 7, 2009 0:19:55 GMT 44767 said:

The one below is from the same sort of angle but is not perspective.

Whats weird about the wagon is that it looks like the perspective is back to front, ie the far end looks bigger than the close end. Its not, I had to measure my monitor just to check I suppose the brain is saying distance is smaller, but its not, so brain says its bigger, classic optical illusion.