Is CAD for Me?

Nothing in the workshop for now, as I've only just returned from hospital with a new left knee joint. I suppose at tome time they'd fitted white-metalled liners and a Stauffer grease lubricator...

My last but one pre-op foray was to the exhibition at Doncaster, but I don't think I will go there again. You'd expect a major racecourse to be easily accessible in outer suburbia if not countryside, not practically in the city centre or the rail-freight terminal. Rip-off food prices too, but blame the race-course managers, not the exhibition organisers, for what the equine world probably thinks pennies. Then via a stop in the Dales, to Kendal to collect my purchased Myford gearbox. The lady in the box on the dashboard sent me on a very strange point-to-point to the seller's home, though to be fair to her, she could not have known a particular road was closed for repairs.

So what to do while temporarily crocked and glad I'm not a race-nag....

I can still fight with TurboCAD. I thought basic 'Access' was hard!

Still, I had a basic-level geological article for my caving-club Journal to complete, and TurboCAD grudgingly allowed me to complete one 2D and two 3D diagrams for it. In time akin to knacker's-yard stagger rather than 13.375 Furlongs Handicap Chase.

They actually look-half reasonable but I was creating diagrammatic sections of hills; and Nature no more builds hills to ISO-approved metric milli-furlongs, than horses to integers of hands (1H = 101.6mm). So no worrying about more than visual alignment, and then by co-ordinates. Assembling 3D drawings elements by the "approved" course totally foxes me, and I've gone to ground on that one.

Nor did I need do what the CAD experts all like to show off 'cos they can: model the item isometrically then take off orthogonal projections from that. Apart from not finding any instructions for that anyway, my workshop drawings need to be orthographic, and I try to make them as accurate as possible (but know how to re-type "wrong" dimension values...). Why waste hours crashing into 3D CAD hurdles too high for me, when I want to make the 3D objects, not their pretty brochure pictures?

I did try Alibre, briefly, to see if it's easier than TC; but an unintended and unexpected succession gap between shop-bought and subscribed MEW issues didn't help me, then I saw the price for the real version. I've also sampled Fusion 360 (free for hobby and student editions presumably, like Alibre's trial edition, stripped of key functions) but went nowhere with that either. Also, both of these seem to insist on isometric-first. Bit like trying to learn to sing from The Ring Cycle libretto.

Ah well, I've still my A0, commercial-standard drawing-board...

Edited By JasonB on 04/06/2019 16:05:29

I'm glad its not just me, I get bored trying to make something work on these programs, I tried all the so called simple ones and always end up using pen and paper, in my head designs and reading drawings.

I'm computer literate and not daft but CAD drawing for me is lots of time doing nothing.

Martin P

Edited By JasonB on 04/06/2019 16:08:59

I think learning CAD is like learning French, to start with you have to look everything up and translate what you want to say, eventually you will think in French and be able to hold a free flowing conversation.

Mike

Edited By JasonB on 04/06/2019 16:09:18

I find 3d modelling considerably easier than trying to get my head around the techniques to represent 3d items as 2d drawings. It's hard enough drawing something that exists, but creating something new isn't worth my time. 3d modelling is MUCH easier if you don't have the 2d background.

I use Fusion, but they're all complex programs with a bunch of features that I'm never going to need so learning them takes time. But the same applies to common programs like Word.

Edited By Nicholas Wheeler 1 on 02/06/2019 20:23:16

Edited By JasonB on 04/06/2019 16:09:36

Not really, I failed O-level French with grade 9, but 3D CAD is pretty simple as that's how I think. But then again I are an engineer.

Andrew

Edited By JasonB on 04/06/2019 16:10:02

Hmmm. Interesting. Obviously how well you manage to learn CAD is extremely individual, as is the extent to which you wish or need to explore its darkest depths including Isometric models.

I have seen others similarly to Nicholas admit finding it hard to think of a three-dimensional object, orthographically. I don't find that, but perhaps from familiarity with engineering drawings and OS Maps.

I do find awkward, the unfolded-box model used to teach orthographic projection. To me, it flaps empty projection-planes about in space, so is too abstract. Instead, I pick up a simple, real object and by looking at each face squarely, see at once what goes on the plane behind (1st Angle) or in front (3rd Angle) of it. I.e. the object rather than projection plane is the more important.

'

Learning to draw manually does not require much tool-manipulating skill, so you can concentrate on the subject of the drawing, hence if it's original to you, its design. There certainly are difficult topics in manual draughting, such as interpenetrations, developments, loci and what my A-Level Technical Drawing course called "Lines In Space"; but these are all graphical plotting skills related directly to the subject, and use no more tools than any other part of the drawing.

On the other hand, Computer Aided Draughting (not "Designing" places a vast wall of complexity between rough pencil sketch and printed workshop drawing; even for simple orthographic drawings of straightforward items.

Isometric drawing manually is harder than orthographic, entailing a lot of plotting to make even simple circles let alone interpenetrations look right. In the workshop though, normally you need orthographic projections. Isometric drawings are good for assembly-drawings and helping you visualise a complicated item, but are not otherwise as important or useful as the orthographic images.

'

I found 2D CAD hard enough, and 3D too hard beyond a very basic level. I think the comparison with other subjects like languages interesting but erroneous, because we learn unrelated disciplines and their own topics in their own ways, and to personal limits on general and subject learning.

One limit is the level of abstraction - I understood (x, y, z) graphs in Maths at school because they related directly to familiar orthographic engineering-drawings and Ordnance Survey maps (I enjoyed walking as a hobby). Yet Matrices baffle me totally by being merely abstract sum-boxes with non-intuitive names and no link to anything.

I compare learning to filling buckets with water, on a beach; each sized for a particular discipline or topic. The seas of the world are inexhaustible, but once you have filled a bucket, any added water just overflows.

'

Isometric drawing in CAD lets you place a picture in the corner of the workshop drawing to help in visualising the part. The Hemingway Kit drawings use this. At professional level, it allows ready construction of assembly drawings and publicity pictures. For the amateur drawing for own use, these advantages are secondary at best, and outweighed by the sheer difficulty.

I bought TurboCAD hoping to learn it enough to help me draw the engine and transmission I need design for a miniature steam-wagon whose archive materials are merely a few old photos and some leading dimensions. I knew CAD has many advantages, such as copying and pasting similar elements, and that it would be a lot to learn; but I'd not bargained for it being so dificult.

Fusion360 deterred by its brashness, but more seriously, by being so confusing. My mistake with Alibre was that after some progress with TC, starting a very different package would be silly and costly. Also, both use isometric drawing first, so very roundabout indeed, and far harder. To its credit, TurboCAD allows 3D-first too, but gives you the choice.

That is NOT a matter of ability to visualise 3D items in 2D - that applies in manual draughting too.

It IS a matter of learning software unsupported by training materials. (Videos? Not all of us can learn from a video of an expert demonstrating his skill.)

CAD adds many concepts and traps non-existent in manual drawing. For example, tools not responding as they should, because they need certain, hidden conditions from previous stages. If you do not know these concepts and traps, you cannot learn CAD properly, but no-one tells you.

We are amateurs trying to use software for professionals, by publishers who expect it to be taught in full-time, professional courses. (I don't think SolidWorks and AutoCAD, extensive in industry, are even available for the amateur.) We can only buy the software then try to understand it without proper literature, tuition or prior understanding of CAD principles.

If I'd have stuck with MEW's Alibre offer I would now have a pretty picture of a scribing-block, but then what? I already have a real scribing-block. It would not help me draw my wagon engine!

Edited By JasonB on 04/06/2019 16:10:21

I hope your knee is a good one, Nigel.

As for the location of the Doncaster show - bear in mind that being where it is makes it accessible to people travelling by public transport,. Last year I went by train and bus, and walked back to the station on my return. A taxi would be affordable.

Coming by car I it's dual carriageway all the way from the M1 so hardly that difficult to access?

Neil

Edited By JasonB on 04/06/2019 16:11:27

It depends what you want to do; I have a whole host of bits that I have designed in Alibre and 3D printed. Even this knob cap (one from the USA would have cost me $23... I am going to redo in green).

Edited By JasonB on 04/06/2019 16:10:50

Fusion advice, look for Paul McWhorter, i think I’ve spelt it right, on utube. He emphasise and explains well the need to understand sketching. It is fundamental to making it work. He spends a few tutorials on this which lifted the scales from my eyes stick with his as he can be a bit repetitive.

Justin add it’s not clear the sketching bit is the 2D drawing which is then extruded to get the 3D result.

If you’ve ever fallen foul of “constraints” , I have, he explains how to deal with it in simple terms.

Try it.

Edited By JasonB on 04/06/2019 16:11:47

Fusion advice, look for Paul McWhorter, i think I’ve spelt it right, on utube. He emphasise and explains well the need to understand sketching. It is fundamental to making it work. He spends a few tutorials on this which lifted the scales from my eyes. Stick with this as he can be a bit repetitive.

AJust in case it’s not clear the sketching bit is the 2D drawing which is then extruded to get the 3D result.

If you’ve ever fallen foul of “constraints” , I have, he explains how to deal with it in simple terms.

Try it.

Edited By ANDY CAWLEY on 03/06/2019 19:19:05

Edited By ANDY CAWLEY on 03/06/2019 19:20:24

Edited By JasonB on 04/06/2019 16:12:07

I've tried it and it's brilliant!

I was going to post my latest design but it does not appear to be possible, even as a jpg.

I got started after watching 3 beginners videos by Lars Christiensen.

Brian

Edited By JasonB on 04/06/2019 16:12:31

CAD. Without it i would not have moved forwards in my professional life. I Started with Turbocad then moved to Autocad after 15 years i moved to Solidworks.

Now 10 years in to it it would take some beating. But thats my preference.

I would also add that its one thing being able to use a CAD system but designing conceptually is another thing all together. Not all people can do it

Bri

Edited By JasonB on 04/06/2019 16:12:55

Brian

Look for Cute pdf and download the shareware version. You can then use Pdf’s to display your work

B

Edited By JasonB on 04/06/2019 16:13:17

Neil -

Thank you for your good wishes! I received the letter today asking me to make an appointment with the physiotherapist.

'

Doncaster Racecourse: easy if you know the area. I don't. Very busy roads, many large, complicated junctions, few sign-posts. Having to concentrate on fast-moving, heavy traffic while trying to listen to the sat-"nag" I dare not read, looking for any signs that did exist; counting confusing roundabout exits. In such conditions the sat-nav cannot keep up, so becomes very ambiguous. It did lead me there, but via a trading-estate and the rail-freight yard.

The car-park was signed "Full": had to cross that very busy urban dual-carriageway and look for the alleged "Overflow" car-park - no signs, either for or of.

Finally, in one last attempt before giving up and driving on to the Dales, I came round that big roundabout once more, spotted a single space in the car-park and succeeded in getting in.

Public transport? Excepting I needed to drive elsewhere that weekend anyway. The North of England is very easy to reach by train from Weymouth (via Bristol), but distance and times would enforce a prohibitively costly two nights' accommodation in Doncaster.

'

On CAD, I want to learn it sufficiently to produce drawings good enough for making functional items in my own workshop, to my own designs.

TurboCAD's very meagre materials, including its extremely poor on-line "Manual", at least go straight into using that package.

Alibre: I felt that MEW exercise was drawing a scribing-block by rote, not understanding Alibre. When I realised my mistake, I deleted the lot. I did though, find how to improve the block's stability by enlarging and recessing its base!

I've subscribed to ME for years and started buying MEW partly for Alibre, but a pensioner now, will probably stop one or the other, or both, subscriptions at next renewal.

Fusion 360 looks forbiddingly difficult, and is even worse in assuming you already understand CAD concepts and want to make pretty pictures.

I bought two books from TEE Publishing on CAD basics, one by D.A.G. Brown, the other by Neill Hughes (whose publisher can't spell "metre"; but they can obviously only be very general. Brown's book is perhaps the better, despite its rather out-dated cover photo, by concentrating on orthographic engineering drawing; Hughes is really wedded to the pretty pictures approach.

-

Boiler Bri -

Ah, but with great respect you are illustrating the point I made, that all these CAD programmes are intended for use by professionals taught them professionally and fully.

Oh yes, I know ability to use CAD does not itself mean you can design or make anything. I saw examples at work of CAD detail-drawings meeting artificial "design review" standards of appearance, of items thereby very difficult or impossible to use!

Paul (TheCAD) Tracy once offered TurboCAD classes, but they were expensive. I don't what happened to him but he was the only agent for the only decent-quality CAD software available at a reasonable price to amateur engineers, and he used to advertise in ME and MEW. I bought my copy, on a CD, at a model-engineering exhibition.

Solidworks and AutoCAD are for trade and university buyers only, judging by their web-sites, and probably costlier than a fully-fitted Myford Super 7.

'

I'll stick with TurboCAD. I cannot draw isometric assemblies in TurboCAD of more than 2 or 3 simple, concentric elements, but luckily, unlike its rivals, it lets me make multi-part orthographic drawings directly.

Edited By JasonB on 04/06/2019 16:13:33

Sorry - I did NOT intent that stupid 'wink' sign.

I forgot it appears from certain punctuation marks and I can see no way to edit it away.

Edited By JasonB on 04/06/2019 16:13:52

Thanks for the info Boiler Bri (that's such a good name) but I've managed to save the Fusion 360 design as a .jpg.

Now this may be just a pretty picture but in the Fusion 360 program it is possible to take off engineering drawings with whatever dimensions are necessary or to cnc from solid or to have it 3D printed to use as a casting pattern. It is also possible to add it to an assembly and check for fits (but not tried that yet).

It is not an expensive program, it's free to hobbyists and the help from AutoCad is freely available.

Brian

Edited By JasonB on 04/06/2019 16:14:14

Nigel (et alia),

Always precede a right-hand bracket with a space.

You should be able to edit out a 'smiley' by positioning the insertion point after it and pressing back-space a few times, then retype with the space where I've suggested.

Best regards,

Swarf, Mostly!

Edited By JasonB on 04/06/2019 16:14:59

Just read Nigel's posts on CAD with some dismay! I hope no-one is put off having a go at CAD by his personal experience.

Nigel explains why he finds the software difficult, but I think he has misdiagnosed the reasons. The real problem is Nigel has very clear ideas about how 3D CAD packages should work that don't match what the software actually does. The result is a series of fights from which Nigel inevitably retreats bruised and defeated. He is trying to hammer nails with a screwdriver.

The cure is to dump all previous drawing experience and approach 3D CAD with a completely open mind. Unfortunately 'unlearning' is extremely difficult, especially after years of successfully doing the job.

Learning 3D CAD isn't quick or easy, but it's certainly possible. At first I struggled with 3D until I had a light-bulb moment and suddenly 'got' it. After that progress was rapid, though I'm no expert!

In practice, most of my simple workshop ideas are sketched on paper. There's a level of complexity where I reach for 2D CAD, mainly because it can draw accurately, and layer drawings on top of each other to check fit, define construction lines, or add clarity. It's a valuable way of creating neat drawings for later reference that can be changed later.

3D becomes useful when I need to visualise complex shapes not least because the way they are defined in software often suggests ways they might be machined in the real world. Thereafter, because objects are defined by their parameters, 3D CAD opens the door on modelling assemblies (with joints), simulations, BOM, FEM analysis, photo-realistic rendering, G-Code & CAM, Isometric Drawings and much else. In the sense 3D CAD works with objects, they're not really drawing tools at all, and I think that's what's blowing Nigel's fuse!

He's not alone. Computers aren't for everyone. Apart from interest, there's no point in learning 3D unless you need it. Unlike me, you might have better things to do with your time, like making the real thing,

Here's one I did earlier. It's Stewart Hart's PottyMill implemented in Fusion 360. The picture is a photo-rendering of a part-built engine used to show a stage in the build process. Each part is individually defined, and isometric drawings can generated from them for the workshop. Or G-code. Or images. Parts are 'assembled' by combining them in their proper relationships by modelling joints. Joints represent real-world conditions, like bearings, slides, and fixed connections. In this CAD model, on-screen, the flywheel rotates and turns the crank, and - if it were connected - the crank would work the invisible piston hidden inside the cylinder. Or the other way round. If any of the parts are changed, then the assembled model follows suit, perhaps throwing an error if the parts interfere.

If I wanted to, I could use the CAD model to explore ways of improving Stewart's engine, perhaps simplifying construction by tweaking the geometry, or beautifying it by complicating the parts, or adding a governor, or playing with different paint schemes.

Fair amount of trouble to create CAD models, but they're far more flexible than isometric drawings. Only you can decide if CAD is worth the bother.

Dave

Edited By JasonB on 04/06/2019 16:14:36

In answer to Nigel, perhaps a 2D program would be more suited, such as DesignCad (one I have used for many years) This is more like an electronic drawing board but with lots of options.

The reason I'm dabbling in Fusion 360 is that I have a set of drawings for a 3 inch Fowell-Box Road Locomotive done with pencil and paper with errors noted on the drawing as 'not to scale', and my plan is to make this engine in 1.5 scale.

My plan is also to have some patterns done by 3D printing and also to try CAM at some much later date.

I found Fusion 360 VERY difficult a first, so much so that I gave up at one point but then tried again after discovering the videos by Lars Christiansen.

Brian

Edited By JasonB on 04/06/2019 16:15:20

Wow! 3D CAD seems wonderful. Can aged brains cope with the learning involved? I know nothing of 3D CAD (and almost as little about 2D CAD). Allowing for the presumed differences between the various applications' user interfaces, would it be possible for someone to provide (in MEW?) an introduction to the common concepts of 3D CAD? It seems that potential users stumble over the concepts, even before they have to wrestle with complex and confusing user interfaces, which, I assume, vary considerably from one package to the next.

Edited By Kiwi Bloke 1 on 04/06/2019 10:37:34

Edited By JasonB on 04/06/2019 16:05:53