CAD for novices.

[Retired]

Hi,

I'm still around and keeping busy but have not posted on the forum for quite a while. My current projects are outside the scope of this forum but I hope the following story will be of use as CAD (computer aided design) is relevant to electronics and electrical work in general.

https://www.vintage-radio.net/forum/...ad.php?t=48719

The above link is to a thread I added way back in December 2009.

The story actually started when I bought my first computer about 14 years ago. I always liked technical drawing and was top of the school in the subject 50 years ago. I now wanted to use the computer rather than my drawing instruments so obtained AutoCad. I spent ages trying to use AutoCad; I couldn't even draw a straight line (didn't know to press Ctrl whilst adding a line) and as the background colour was black I didn't even know how to change this to white. In short I was a computer dummy and even worse with AutoCad. I don't give up easily but CAD had me beaten.

Over the years I've spent hundreds of hours trying to master CAD; I've bought a number of both ordinary drawing and CAD programs and even downloaded a number but every one I tried ended up in failure. In the meantime I did improve my computer skills.

I tried to master CAD once again as shown in the above link and I did make some progress; I bought TurboCad and was determined to learn its secrets; I could draw a straight line by now but connecting other lines to it was still troubling me; I finally managed through fierce determination to draw a clock ring plus other basic drawings but it was at an incredible slow pace with huge frustration. I then started to get worse rather than better; it reached the point where I could only watch the TurboCad tutorials for about half an hour before my eyes glazed over and I wanted to sleep. I spent a lot of time getting nowhere in fact I was going backwards and the bits I had learned started to become increasingly harder. Once again I admitted defeat as it was consuming great amounts of time.

Our climate is usually dire at the best of times but during our joke of a summer this year I did a lot of work outside until it became too cold to carry on. During yet another dire weather day about a week ago I thought I would once again have a go at mastering CAD.

I had used emachineshop previously to draw full sized gears using the EMS spur gear wizard which was a tremendous help and very easy to do. I downloaded EMS once again as it is totally free and set to with renewed determination and full of enthusiasm.

The beautiful young lady (Aurora) tutor on the EMS videos did rather distract me but what she demonstrated looked so easy a child could grasp it. At first things were slow as I attempted to draw but suddenly things began to make sense and four hours later I had produced my very first fully scaled 2D engineering drawing using CAD. I worked so hard at concentrating I felt tired out but I was very pleased with my efforts and especially with the result.

The following day spurred on by this success it only took an hour to convert the same drawing to 3D. I almost fell from my chair when the 3D drawing I had just produced could be viewed in full 3D; I could rotate it and view from any angle; to say I was amazed is an understatement. I was utterly gob-smacked. What a huge step forward this was for me; after 14 years of abject failure using CAD I now could not only draw using CAD in 2D I could draw in 3D. Since then I've been practising and although I had successfully drawn the steel electro magnetic clutch adapter needed for my latest project I had difficulty in adding the snap ring groove (circlip groove) to the drawing.

I watched the video tutorial showing how to draw a pulley using “revolve” and thought it would be easy adding a simple flat bottomed groove but it just would not happen. I then browsed EMS forum and sure enough the question had been asked and the answer was simple; use the “groove” function. It is so easy to miss something like this whilst on a steep learning curve. Clicking on “line/machine” opened up a box and adding the groove details was dead easy; at last I had a very accurate (to three decimal places) 2D drawing of the clutch adapter and also the icing on the cake was being able to view this in glorious 3D. I had arrived at last after 14 years.

The above story is to demonstrate just how hard I found CAD to be; I couldn't get my foot on the first step of the CAD ladder in fact I couldn't see the ladder but now I'm finding CAD to be very interesting indeed; I can design and draw and am truly amazed just how easy it is to use EMS CAD. It appears to be in line with the way I think and does as I expect. I can draw lines; divide lines; join lines in correct places add holes which are described as “air inside”; I can erase a line without erasing the entire drawing; yes I've erased many drawings in error. Circles are drawn exactly where intended as are rectangles; why have I had to suffer so long before producing my first fully scaled CAD drawing in 2D?

I think I have the answer. EMS CAD is designed and supplied totally free in order for customers to design and draw components they wish to have made. EMS is a facility rather than a workshop; just about every machine is available as is every material at my fingertips. I can specify the machine and the material then draw the component; submit the drawing to EMS for checking and to obtain a quote; once the drawing is passed and the quote accepted; simply pay and sit back to await the item/s to arrive; all from my computer. EMS CAD is to encourage people to order through EMS.

EMS CAD is set up totally differently to the other CAD programs I've tried and failed with. It is basic and intuitive; it is easy to learn but powerful; The drawing page is not crammed with lots of tool bars containing icons that when clicked on open up a whole list of options; it is simple but with enough options to enable complex drawings to be produced. I was intimidated by the sheer amount of options on the other CAD programs and I believe it was this that caused my troubles; too much to take in too quickly; it used to tax my single brain cell to the limit.

A week ago I was abysmal at using CAD so please see my humble efforts below. My computer graphics drivers are not compatible with EMS; I can draw OK but I'm unable to change the EMS format file to any other file type and it refuses to save to “bit map” so in order to get around this I can save the 2D drawing to zip file and add the zip file to the forum.

To use please click the zip file and hopefully the 2D page should load; this is uninteresting; near the top of the page is a pyramid icon next to a tick; please click the pyramid; this opens up the 3D image and this image can be rotated or viewed from any angle by using the mouse. For those used to CAD this will mean little but to a CAD novice like me I feel I've moved forward light years in a week.

I'll try to add a couple of drawings for you to kick around; one is the clutch mounting the other a simple design showing comb joints as used in wooden items. (Don't forget to click the pyramid).

Here is EMS website for the CAD download.

http://www.emachineshop.com/

My current project is to install an electro magnetic clutch onto my Union Jubilee wood-turning lathe; this clutch was removed from a Daewoo Lanos car air conditioning compressor. The lathe is also being fitted with a 2.2Kw 3 phase variable frequency drive (VFD).

I don't half ramble on but boy am I delighted.

Kind regards, Col.

[davidgem1406]

Nice and interesting writeup Col.

I will be giving that CAD a try at some time although I use MS Visio for most of my drawings.

Dave

[Refugee]

I may have a fiddle with it on my windows adapter for Linux.
I have been getting a full version of an electronic CAD program to create symbols for vintage components and it is working with the adapter on Linux and also i have been having some success.
It does take a long time though.

[brenellic2000]

The trick with CAD is to know how to draw in the first place! It far easier to learn CAD if you have drawing office experience and engineering knowledge to be able to achieve what you have drawn. Too many American based CAD systems try to do the thinking for you.

I absolutely hate AutoCad, VersaCad and TurboCad. Trouble is my foolproof 1980s CAD is obsolete. Oh the joys of T squares, set square and French curves... phwarrh!

Barry

[Retired]

Hi,

Good luck with your endeavours Dave; CAD is a very enjoyable pastime during winter when it's too cold to get serious in the workshop.

I'm sure you will enjoy fiddling with it Refugee and as both you and Dave are obviously into electronics I'm pleased to add another side of EMS it being their electronic CAD which perhaps is even more relevant to the members of this forum;

http://www.pad2pad.com/

I've not tried pad2pad but if it is anything like EMS CAD it will be easy to understand and the lovely Aurora is there to guide through the videos.

It was the above clutch mounting I drew as a first attempt; I really needed six very accurate hole centers around the outer face of the flange as these needed drilling and tapping for mounting purposes. At first it was rather difficult but now a matter of seconds to add as many equally spaced lines it being a single "repeat" click for each. After doing the 2D drawing I very accurately cut the drawing out to use as a template punching on each center. This could be applied to many applications such as when designing a new chassis and wanting to lay out the components. the pictures below show better than text can explain.

I'm sorry my computer won't allow me to transfer the EMS file in a format recognized by this forum hence I had to convert to zip file which is a bit of a pain to open but at least it is there for those interested. Since I drew the 2D for the template I quickly grasped what I was doing and went to 3D. The clutch mounting 2D drawing took around 4 hours and the conversion to 3D about an hour; this is lightening speed considering I was unfamiliar not only with EMS but useless at CAD in general. In order to add the two pictures I had to take a digital image directly from the monitor using my camera then download allowing me to use Gimp2 for re-sizing. I'm buying a new computer shortly so it's not worth the money or hassle updating this computer.

Once a few basics are understood then CAD suddenly opens up; I'll stick with EMS but for anyone more ambitious then EMS would make an excellent starting point before moving on to the more complicated CAD programs like AutoCad and TurboCad.

Kind regards, Col.

[brenellic2000]

Yikes, two swings of a compass, three flips of a set-square: Done! 30 secs... or 1.5 mins by CAD!!

But seriously!! Engineering drawings always say 'Do Not Scale' for a good reason as even a dyeline print can shrink or expand marginally - and some CAD systems don't always print 1:1 or to the correct scale, even when the paper size is selected for a generic printer, or when converted to another file format . ALWAYS check the print for correct scale! It does happen... believe me!

TTFN
Barry

[Retired]

Hi,

Many thanks Barry; yes I fully agree with what you say. I've been using my drawing instruments for the last 50 years but can't draw accurately to three decimal places in fact given my bi-focals I have difficulty separating the lines on a protractor.

I could have made a fair attempt at the above simple drawing as you say Barry using my instruments but I've said I wanted to crack CAD and that is really what I added this thread for. I actually turned the new steel mounting first taking direct measurements from the original but I wanted the six holes accurately spaced as the steel blank I had did not give much spare metal to play with.

The original clutch mounting was part of the compressor aluminium casing and I had to cut it free using a hacksaw in order to remove the coil which otherwise would have been destroyed as it was so tight; I needed the new mounting but didn't want to weld so decided to attach using six 5mm countersunk socket screws.

Using my drawing instruments would never allow me to view my drawing in 3D the way I can on the monitor. Using a rubber to delete a line takes longer than a couple of mouse clicks and isn't as neat or accurate either; make enough mistakes and the rubber eventually goes right through the paper.

I have an HP Laserjet P1102w printer and when I printed the clutch mounting drawing I checked it using my digital vernier caliper and the drawing was bang on. The result can be seen in the picture where I used double sided adhesive tape to secure the printed template.

I'm still very much a CAD novice but at last I'm now grasping the method and hoped my endeavours would encourage others who have suffered similar problems with CAD to once again have a go.

I won't try to expand on my lathe project but thought adding details of EMS might be useful.

Kind regards, Col.

[dave cox]

Ahhh, this brings back memories.

I was once fortunate enough to get paid to 'play' with state of the art 3D CAD systems. Whilst occasionally demonstrating such systems (especially to mechanical engineers) a common question was "how do you draw a line ?". These systems are (almost) always built on 'boundary models', these represent the closed surface of a solid object as a face / edge / vertex 'hyper-graph' (a complex data structure obeying Euler's 'rules'). Although it is usually possible to just draw an line (aka edge) you won't enjoy the rest of process of turning that into a valid closed surface.

It will be worth looking through your CAD system to see if it can do 'parametric modelling' - this is real fun to play with although exactly how useful it is another matter

I use a 2D freebie, those 3D ones are super but can waste a lot of time making it look wonderful rather than getting the job done.

[Nymrod121]

Col, PM on its way,

Kind regards,
Guy

[Retired]

Hi,

You sound to be light years ahead of me when it comes to all things CAD Dave. For a CAD novice simply drawing a straight line is a nightmare let alone trying to draw it to length and in the correct place; fortunately I can now mange to draw a line and even join others to it but I still have a great deal to learn.

Thanks merlinmaxwell; yes it certainly does take time using CAD but I am making progress and what used to take forever I'm now doing much quicker; as I've stated simply drawing a straight line used to really drive me absolutely barking but drawing such a line is now a rapid process.

I don't need either 2D or 3D drawings for my projects but I've turned learning CAD into a project and am enjoying it. I hope other members have a go with CAD as it is a whole new world to explore.

Thank you Guy for your delightful PM it is much appreciated and I've just replied.

I've been practicing CAD all morning and progress is very slow; I go through periods like this but if I stick with it I also go through periods where things suddenly click allowing me to move forward. I'm in no hurry because I would quickly become bored if things were easy.

Kind regards, Col.

I don't need either 2D or 3D drawings for my projects

Ah the good old 1D drawing then?

I have found that printouts are very accurate and for doing a panel a print and one of these http://www.axminster.co.uk/axminster...7/?src=froogle is quick and works out very well indeed.

[brenellic2000]

It may help, when learning CAD, to first draw a border as if it were a sheet of paper (A4, A3, A2, good old Elephant even!) as you can better visualise where to place the line relative to other bits. AutoCad and its ilk works on a sheet of paper of infinite size - you add the paper size later, which always strikes me as odd.

Its then a case of simple co-ordinate geometry to work out where to place the next point. There was no standard CAD system when I started with CAD in the 1980s and you really had to get to grips with that software. Alas AutoCad now dominates - but to my mind it is the most over-rated junk! Most freebies are very limited - and even AutoSketch (the easy AutoCad) was utterly hopeless. Forget 3D unless you really, really need it.

It really does pay to be tutored by someone who knows the software backwards... before you discover its limitations. But which software to choose - that really is the unanswerabale $64,000 question.

When my DOS based CAD systems dies, I doubt I'll bother to learn another and will simply go back to drawing board! Far more pleasurable and foolproof.

Barry

PS: Of course CAD drawing's accuracy to 0.0001" is only as accurate as the blunt punch and swipe with the mallet - optical or not.

[davidgem1406]

Hi Col,

I have to admit that I don't do a great deal of drawing that requires me to be very accurate other than the times I make a new tuning scale.

Mostly I make wiring layout drawings for units I have to dismantle to do work on the chassis, mostly because of bad corrosion.

Then there is the need for redoing a schematic diagram sometimes as the original may be very poor.

The most accurate work I do is if I need to make a PCB for a project then I use a software package designed to do that job.

Dave.

P.S. some sample drawings

[Retired]

Hi,

Nice one merlinmaxwell; a 1D drawing is produced between my ears and is usually the way I go; in the workshop a 2D drawing is a sketch on a bit of scrap paper but 3D is the icing on the cake. Thanks for adding the optical punch details.

Thanks Barry for the tip to add a border first; it is very useful. Regarding paper size; this alone was enough to put me off using TurboCad; I found the palaver of adjusting paper size much too complicated and this before even starting to draw. I don't have the benefit of a CAD tutor unless I watch lots of tutorial videos and this is a slow way to learn but as I want to learn I accept I have to put the time in; the young lady tutor "Aurora" on EMS videos is delightful.

Many thanks for taking the time to submit the picture and downloads of your excellent work Dave. What you have demonstrated is exactly what I'm trying to encourage by adding this thread. There must be many people who are interested in CAD for a number of reasons but who simply cannot get to grips with the CAD basics; I'm one of them and I don't mind sharing my story of my struggle with CAD. Even experts at CAD had to start at the beginning. As you say Dave you want accurate drawings for your schematics or to draw a PCB layout and a suitable CAD program with knowledge of how to use the program then becomes of use.

I don't need to know about vintage radio after all I can simply turn a radio on and listen to it without knowing what a cap or resistor is. I don't need CAD either but if I think along these lines I might as well sit in front of the telly all day cigarette in one hand lager in the other hand watching someone kick a ball around a field. No offence meant whatsoever in the above comments but I choose my own lifestyle.

I do my many hobbies because I'm interested in them and make many new friends through the various forums associated with each hobby. A number of my hobbies are extremely useful such as wood/metal working/DIY as they save considerable money allowing me to do jobs around home without having to get someone in. I've learnt the skills required over the last 50 years; some skills I use a lot others seldom. I'm not veneering every day but I learnt how to veneer.

I was taught technical drawing at school but this doesn't mean I can't try CAD just for the interest. I don't need CAD neither do I need vintage radios; I'm simply interested in both which is good enough reason for me. I'm always learning new things and techniques and like to share my progress as many members do; I'd much rather be positive and try to encourage rather than negative and not bother. I also ramble on but I'm never bored.

Kind regards, Col.

[brenellic2000]

Early versions of TurboCad were a nightmare; you first had to set the correct aspect ratio for the screen, so that a circle actually looked like circle! It was hopeless... but it sold well because it was full of hype and promise!

I can fully understand your desire, Col, to learn CAD - once mastered it can be a real bonus. But it is a steep learning curve as one has first to understand the logic used by the originators of the software - and quite often their logical is quiet... errr, illogical!

In the 1980s, experienced CAD operators could demand any salary they wanted - as everyone wanted to go down the CAD route... just because. The irony was that many early CAD operators had no technical skills - they merely 'traced in' the skilled engineer's work, which often led to errors and some pretty awful drawings - but hey!, this was the future!! Then the bubble burst and CAD operators vanished as CAD was taught in engineering colleges. Many 'engineers' can now design something on the computer but are clueless on how to make it! That's not engineering to me... but its 'progress'!

Persevere - you'll get there!

[Retired]

Hi,

Thanks Barry; I'm sticking with it in fact I've just had a most frustrating day and a half going backwards. I can draw two parts of a simple jig but am finding it impossible to connect them together as there just doesn't appear to be the option I need available; I keep receiving messages saying these two lines cover each other which is not allowed. I'm mindful that EMS CAD is linked to machines so as you say I need to understand what the basic thinking is. If it was easy I would soon become bored.

Do we have "true engineers" these days Barry? The simplest of jobs take lots of dedicated teams to complete. Take for example something like replacing a street lamp. Our local council decided the old concrete lamp post was dangerous so a new steel one was to be installed; it took over eight visits by council workmen to replace this lamp; each time they arrived with lots of kit. A couple of weeks ago we suffered a bit of windy weather which completely lifted the top of the new lamp right over on its hinge exposing the innards to the elements. I immediately emailed the council who eventually sent a guy to remove the lid completely? Our lamp is still not working but as you say Barry this is real progress.

I was taught by top class engineers as an apprentice in the pit. these engineers were capable of doing very precise hand work such as filing to a thou and at the other extreme they would weld inch plate and RSJ's with ease. This training has remained with me for the last 50 years. In my last job of 24 years it wasn't hard to gain promotion because the average guy is nothing more than a sheep; unable to think unless its about who scored the goal. I'm certainly not what I would consider clever but the competition I was up against was just happy to get the days work out of the way with zero interest in what they were doing and they certainly had no pride in doing their job. Why did I have to explain that an empty plastic cup is supposed to be deposited in the bin provided? I ask you; where the heck is our country going to end up?

Many people are terrified of change; I welcome change but only if it is for the better. I avoided conflict at work because I would explain in detail any changes I was going to make and outline the benefits; I did this at each months team brief; my job was stressful enough without personal conflict adding to it.

I'm pleased to hear that it's not only me who has difficulty in adjusting page size using TurboCad. I find EMS CAD to be set perfectly for A4 allowing me to get straight on with drawing.

At the moment I'm unsure if it is down to my ignorance of CAD or if my computer is not set up for what I'm trying to achieve. When I try to save an EMS CAD 3D image I receive a message stating my graphics are not configured to EMS software. I played around for a week trying to sort this but without success so I'm shortly buying a new computer as this one is now ready for retirement; the original on-board graphics are possibly unable to cope and rather than keep updating bits of this old computer I think it time to upgrade the lot at one go.

Kind regards, Col.

[Retired]

Hi,

CAD is extremely difficult to learn from scratch without a tutor; CAD programs can even put a novice off right from the start as it takes a degree just to size the paper. EMS CAD fortunately is automatically sized at A4 at least it is on my computer allowing me to go directly to drawing. The following story relates to EMS CAD and I sincerely hope it encourages others to stick with it.

I could have easily gone into the garage and fabricated the welding jig shown in the pictures below; in fact I didn't even want such a jig. A friend mentioned he was planning on making a new wrought iron fence of a very simple design so I thought I would try to design and then draw a welding jig just for the CAD practice. The fence was simply two rails; one top; one bottom with either square or round section uprights. These uprights would require accurate positioning abutting the rails whilst allowing access for arc welding.

The jig design is very basic and the jig would cost extremely little to make it being nothing more than short lengths of the wrought iron rail section and a short length of 1" angle iron welded together.

I added a "dogs leg" which would allow full welding access. The jig would be secured in position using two clamps; one to secure it to the rail the other to secure the upright. Not too taxing a design but it took a bit of thought and drawing it using EMS CAD would give me much needed practice.

I then spent a day and a half of total frustration whilst I tried everything I could possibly think of in trying to convert my thoughts into a drawing. Eventually I succeeded in drawing the angle iron and backing support as a drawing and also the dogs leg section in another drawing; both looked excellent in 3D. The biggest problem though was in trying to join the two parts together. I simply could not do it and although I know my computer graphics are old fashioned my ignorance of all things CAD wasn't helping. I could have walked away from CAD forever at this point but unlike the other CAD programs I have used I was actually making slow progress with EMS; I had the two drawings and could even view them in 3D.

In EMS CAD material and machine has to be selected which is very easy; the problem I faced was in choosing the correct machine? I tried "Weld" I tried "bend" and I tried "Auto". I struggled for hours using each and found my lack of progress to be most frustrating; messages kept popping up saying lines must not overlap each other; nudge the offending highlighted line away. I tried this and each time another message followed and if I did as instructed the drawing fell apart; it is extremely important to keep "Saving" allowing the last saved stage of the drawing to be displayed so everything is not lost; selecting on the keyboard Ctrl and "Z" together will step back each time if a mistake or change needs to be made to the drawing.

I was trying to draw as I would make; this is how I always did technical drawing using drawing instruments on a drawing board. I was drawing each separate section of the jig then trying to join them together using "Intersect" and "Group". This worked OK but I could not align the two drawn sections in order to join them together. Other than the "Top" view all I could see in the other 2D views was single rectangles; viewing in 3D brought them to life but drawing on the 3D image isn't possible so once I reverted back to 2D I lost track of which side I was trying to work on; I thought I would end up with steam coming out of my ears.

Time was slipping by at an alarming rate. I then remembered Barry's advice regarding drawing a border. I had been drawing in "Space". A border didn't help me out in this instance although another comment made by Barry suddenly struck home in a blinding flash of inspiration. (one has first to understand the logic used by the originators of the software).

I had been thinking of the sections of the jig as being individual pieces of steel and steel costs a lot of money so waste has to be avoided like the plague. Adding to this I was trying to join these pieces together which was a long tedious process for me as a CAD novice. A single border didn't help but what about a 3D border? I had been drawing in 3D but only thinking in 2D and this was causing me lots of trouble.

In 2D the length and height are used (X & Y) and I selected the "square tool" drawing a random square on the page clicking once at the start then moving the mouse a bit and clicking again; this set the random sized square on the page as a 2D drawing. Now I adjusted the dimensions in the top tool bar boxes for length; height and depth (X;Y;Z) giving me a rectangular shaped block when viewed in 3D; this by the way is dead easy to do and only takes seconds. Now by clicking on one of the lines I could click on "Line" and select machine at the top tool bar. This time though I selected "injection moulding".

I could totally ignore waste as this waste was fictional and would cost absolutely nothing. The reason I say this is that I could now very easily draw lines in any of the views and as long as the lines joined I could select "Air inside" viewing in 3D I had punched a hole right through the block; once I grasped this everything dropped into place and I completed the drawing in less than 15 minutes. I could now do it in much less time after doing it once.

To expand a bit on this; A number of views are available with "Top" being default. If a solid block of material is drawn and can be viewed as a block in 3D then by selecting the view (top;bottom; left etc.) the block can be modified as though you were cutting lumps out of a block of cheese; the area is selected by drawing lines for length and breadth and although I selected "air inside" the "Z" setting can be adjusted to any desired depth but be careful because plus and minus are active; it's possible to add the shape like a patch rather than to remove it; default is plus or positive so try using the minus sign in front of the Z dimension. Strange at first but without the program doesn't know if you wish to add or remove. (air inside which is a wonderful term punches the hole shape right through).

The relief I felt was staggering; I had struggled for so long trying to work the CAD program as I would think but my thinking was not in line with the CAD creators logic. Boy I can be thick but I make up for this by being downright stubborn.

I can now not only draw in 3D but also think in 3D and this is so important whilst never being explained in detail whilst I've read about and watched videos of CAD.

I've moved a huge step forward and am now rapidly gaining confidence in CAD. the day and a half I spent playing around on this one simple drawing could be considered a total waste of my time but is it? During this time I learned a great deal and became quicker at selecting tools; going back to change something; retrieving the drawing because I had saved it; selecting material and machine in fact I learned a great deal and yes it was absolutely frustrating and irritating but well worth it in the end. Thanks Barry for supplying the spark which fired up my imagination.

I hope this story does help other novices because it isn't really about how to draw but the reasoning behind why I wanted the drawing and how I went about it. If you want to learn CAD then please throw your pencil and paper out of your mind because CAD is a totally different technique but once the basics are grasped what a whole new world opens up. The drawing below shows little detail and looking at it the drawing gives no indication as to what it is supposed to be but the 3D image selected in EMS of the same drawing makes a tremendous difference.

Kind regards, Col.

[brenellic2000]

Hi Col

I have some value to society then!! Two of the greatest problems with CAD are terminology and 'layers' - so unless one is fully conversant with your EMS package, it is almost impossible to give advice.

'Layers' (AutoCad) can be very problematical and one can easily get lost. What I think you are trying to draw is, for an analogy, a nut (let's call it segment A or layer A) then a completely independant washer (B) and then a bolt (C) and then trying to combine all three by superimposition as an assembly... and then save it as an assembly (D). That is always possible (in theory!), but it may depend how you saved each 'segment'. In Ormus PC CAD for example, you can save each segment in the lower bottom, centre or at the sheet's origin (x=0, y=0) and then pick up and move each segment and amalgamate them... another CAD package will do exactly the same, but using completely different terminology and methodology.

AutoCad is, alas, now the defacto standard which means most other software at least tries to use the same language and methodology, but AutoCad costs £,000s!

Saving a file should be straightforward... for that software. The problem comes with saving it in another format for use in another software. .DXF was supposed to be the universal interchangable standard.. but like .doc and .docx files... many .dxf versions are not backward compatible - defeating the whole object! But that is a purely commercial decision to force sales of "new improved c**p".

As to your lamp posts, the problem is not one of lack of engineering, but of 'Elf 'n Saftee, Mate!

TTFN

[Retired]

Hi,

Many thanks Barry. I'm not fully conversant with EMS CAD and I've added this thread to encourage others to have a go with CAD; my notes are relevant to EMS so for anyone downloading the free EMS software the details apply.

I've not worked in "layers" so the drawings I'm currently doing are on a single layer but I am aware of layers in the other CAD programs I've tried.

I'm finding EMS CAD much easier each time I try using it; the main item can be drawn then additional items can be drawn on the same page separately and either dragged or nudged into position; they can then be "grouped".

I'm unable to save EMS in another file format and at the moment I can't even save the 3D image as my computer is not configured to the EMS software correctly; the on-board graphics is struggling to keep up but I've already got another new computer on order which should take care of the problem.

Yesterday my chum Mike visited and I was demonstrating my new found skills showing how easy it had become for me to draw both in 2D and 3D. He was so impressed that he too has now downloaded EMS. As Mike is seriously into clock repairs/restoration he asked if it would be possible to draw clock "wheels" with odd numbers of teeth saying 31 teeth was a common number with a 45 degree tooth profile?

I tried using the EMS Spur Gear Wizard and although this will generate any number of teeth the profile is "involute" so unsuitable for his clock work. I was interested to have a go at drawing such a wheel without recourse to the wizard so spent a couple of happy hours in the afternoon experimenting with EMS.

After a number of false starts I suddenly got to grips with this and can now draw such wheels quickly. I had tried to draw each tooth separately and kept losing the plot; eventually I used the tools available; drew one tooth within a 2" diameter circle; divided the circle into 31 and using "repeat" simply stepped each new tooth into position. I then added a central boss and pivot and for good measure removed sections of the wheel to lighten it. I then sent the drawings to Mike who was pleased because EMS will be a huge help to him in future.

Three weeks ago I struggled to draw a straight line in 2D using CAD but now with each session my confidence grows; I can recommend EMS CAD because it is a powerful drawing program without being over complicated. I've still got a lot to learn but so far my progress in using EMS has been rapid.

The pictures below show the 31 teeth wheel with 45 degree tooth profile both in 2D and 3D. I've also included the zip file for those who have downloaded EMS then the 3D can be viewed from any angle.

Kind regards, Col.