errors in drawings

[Dave Jones 1Participant @davejones1]

[Dave Jones 1Participant @davejones1]

would it be possible to create a section of the forum for people to list errors and omissions in drawings for ME articles and models.  I know of several websites and forums that have different ones listed, but it would make things a bit simpler if they were all listed in one place.

Dave

[CirclipParticipant @circlip]

It’s a good idea Dave providing it doesn’t turn into a witch hunt post showing how thick the original designer is, there’s a difference between trying to sort a problem and some being downright bloody rude to try to score points. I suppose that’s down to a Moderator thing, but why should they have to sully their hands when WE are supposed to be grown ups.

 

   Regards  Ian.

[RichmondParticipant @richmond]

I have created a section called “Drawing errors / corrections” under the “Construction Articles” section of the forum.

 

You or we will be able to post questions regarding errors here, We will turn posts into “stickys” once errors are confirmed and solutions found.

 

Rgds

 

[Dave HarrisParticipant @daveharris36943]

What might be a silly request….but!    When revised /new drawings are posted on this site for items in ME and or the ‘Specials’, could they be posted in a format that allows them to be printed on an A4 sheet, the ones for ‘Lusus Naturae’ will not print on one A4 sheet!?

[David Clark 13Participant @davidclark13]

Hi There

Save to computer and resize using a photo program or print and select fit to page.

regards david

 

[Dave HarrisParticipant @daveharris36943]

Moderator, I do not understand what you mean by ‘using a photo programme’, and secondly my printer will not allow me to ‘fit to page’ for these drawings, they appear to be in a format the printer software cannot work with. Sorry to have to say this but my original request stands, please can you use use a format that everyone can access without having to get special programmes/software to deal with them?

[TerrydParticipant @terryd72465]

I suppose that they could be created as a pdf file, but would that be too simple?  We could all print them out then easily. 

 

I’m not sure what you mean by a ‘photo’ program David .  Do you mean software such as Adobe Photoshop or Corel Paint Shop Pro?  As far as I know a ‘photo’ program processes just that  – ‘photos’ for simple printing.

 

Terry

[David Clark 13Participant @davidclark13]

Hi There

Anything that does jpeg as used for photos.

I use paintshop pro but you would probably have got something simple with your camera if you have one.

regards david

[TerrydParticipant @terryd72465]

Ah, right, you mean a Graphics Program.  now I understand.

 

Thanks

 

Terry

[Dave HarrisParticipant @daveharris36943]

Sorry but I dont understand, hence the original question, and from an earlier reply, …if a pdf file is the type of file every computor system can deal with, why cant that be used for the benefit of all when putting drawings on this site?

[Keith LongParticipant @keithlong89920]

Hi Dave

In order to read a pdf, you need to have an application like Adobe acrobat, or Foxit. A jpeg file is more versatile. You can even open the file and print it out using something like MS Word. In MS Word use the “Insert” command, then in the drop down menu select picture, from file (save the drawing to your desktop first). Then double click on the inserted picture and open the dialoge box to adjust size etc. Using just this route I’ve happily fitted both of the Lusus Naturae drawings on to the same page and printed them on A4 paper without going near a graphics program. It’s worth having a look to see what you’ve already got installed on your machine and having a bit of a play.

Keith

[Dave HarrisParticipant @daveharris36943]

Hi Keith,

 

            Many thanks for the explanation, the ‘fog’ is clearing! I will follow your directions later on and see how I get on.

 

Dave

[mgjParticipant @mgj]

In Word you can annotate too quite easily. open, insert – text box. format that as through and you can write on a JPEG . Add arrows etc too.

 

So one easy way is to scan up as a JPG, add any annotations and post it as jpeg. 

 

To open a PDF file is easy if you have Reader.  But to convert to a PDF needs Writer unless other programs will do it. Writer costs ( a lot.)

[Dennis RParticipant @dennisr]

      There is a free open source PDF creator at http://www.pdfforge.org/download haven’t tried it myself yet, but have downloaded and installed it.

      Hope this helps

   Dennis

[Keith LongParticipant @keithlong89920]

OpenOffice also lets you export documents as pdfs and is a free open source alternative to MS Office suite.

Keith

[TerrydParticipant @terryd72465]

Posted by mgj on 23/04/2010 20:27:08:

So one easy way is to scan up as a JPG, add any annotations and post it as jpeg. 

 

To open a PDF file is easy if you have Reader.  But to convert to a PDF needs Writer unless other programs will do it. Writer costs ( a lot.)

 There are several points here which need addressing.  I would prefer engineering drawings etc, to be produced as vector graphics rather than as bitmaps, which jpegs are an example of.  The latter were developed to allow multicolour graphics such as photographs to be compressed to a relatively small size and not for monochrome diagrams.  If you enlarge or zoom into a jpeg it will ‘pixellate’ and eventually become intelligible,mall detail is lost.  Vector graphics have several advantages over jpegs, they are very much smaller files, and can be enlarged to any scale without loss of detail.  If you use the ‘Drawing’ function in Ms Word you are producing vector graphics.  Fireworks and The GIMP are examples of programs which will produce vector graphics and there are many very capable free graphics apps which will do the same..

 

BTW The GIMP is a top class graphics program and it’s name is an abbreviation of The Gnu Image Manipulation Program and will handle just about all image formats (both Raster – which includes jpegs, png, bmp ets ans well as vector graphics),  Best of all it it is Open Source and Free!

 

Regarding pdf files, many word processors will ‘print’ to a pdf file.  Examples include the free Open Office suite of programs which will open all Microsoft documents.  Open office is a wonderful suite of programs (and if you add the free GIMP you have all the document manipulation and creation  programs you need.)

 

You can also download many free pdf creation programs and add ons for MS Word which will allow you to  create pdf documents from Word.  You certainly don’t need Adobe Acrobat Pro to create simple pdf documents and just about every computer sold in the last 15 years has a copy of Acrobat reader and if not it is a small, free download.

 

Also .jpg and jpeg are one an the same thing, jpeg is not a graphics standard as such it is merely a ‘lossy’ compression format,  not really suitable for engineering drawings,(jpeg merely stands for Joint Photographs Expert Group).  See here:

 

 http://en.wikipedia.org/wiki/JPEG

Regards

 

Terry

[TerrydParticipant @terryd72465]

I forgot to mention that CAD programs also produce vector graphics which explains why they can be enlarged greatly to inspect detail.

 

Here is a comparison of vector and bitmap images when enlarged.

 

 Great detail can be embedded in the simplest Vector graphis.  See here for a better explanation:

http://en.wikipedia.org/wiki/Vector_graphics

 

[mgjParticipant @mgj]

Terry – there is always a saying ” The best is the enemy of the good”.

 

I also know what a JPEG is – it has limitations – for my photographic work i tend to use RAW and hten convert to 16bit TIFFS. however, if I want to do vector graphics,. I’ll just open my copy of Photoshop CS3. If I want it big and without pixels  I can use vector graphics and my A3 printer. I’m sure you know the score. However an engineering drawing doesn’t have much fine detail, being mostly black and white lines. But if you like, I can provide you with a 12megapixel photo that is almost A3 sized without interpolation and which will print to about A1 with the right interpolation software, and retain good photo detail. It will be a 150 megabyte file size which might take a little while to download – granted. With a macro lens that could be a pic of an original of something about 1″ square. The point I am getting at is that you can make a JPG into whatever you like. It  doesn’t have to be the 100kb sized web based photo which will pixellate at postcard size..

 

However – here we are talking of drawing ERRORS. You need a scan of the original and an overwrite of a dimension in most cases. The chances of needing to scan a patch of more than A4 size are not great.  (Just as well because most people don’t have scanners that are over A4 size anyway and if A4 is the limit, there’s not much point in worrying about pixellation under enlargement because that will be 1:1 anyway)

 

Also you have to provide these things in a format that most people can print off and use easily. If you don’t  they won’t pass the information on. 

 

With the greatest of respect, if you think I am going to be arsed to annotate a drawing, scan it, import it into Photoshop, convert it to vector graphics and then post it up on the internet – just so you can enlarge it so some fantastic size without it pixellating! I have better things to do, and you are overlooking the fact that there are many people out htere who may well have very valid observations on drawings,  but have not the faintest idea of what we are on about, or the interest ot find out, or the inclination to go trawling around to find programs that will convert to vector graphics, nor the desire to learn to use them when they have got them. And I certainly am not hopping about the internet to import programs which I am likely to use once every 2 years or so –  if that.

 

However, I’m quite happy to annotate (by hand if need be) and post a jpg which will print up actual size of the appropriate section of drawing, which is all one needs for this purpose.

 

We haven’t by the way addressed the problem of checking the corrections. Or do we just accept that any submission is correct and machine accordingly? Which is a great deal more important than some vector based graphics diagram.

 

The best is always the enemy of the good.

Edited By mgj on 23/04/2010 23:19:23

Edited By mgj on 23/04/2010 23:24:20

[mgjParticipant @mgj]

Terry – your argument about  pixellation is perhaps slightly awry.

 

If you enlarge enough bitmaps will break down, and if heavily compressed JPG will show the underlying 4×4 or 8×8 matrix with which the algorithm works. The answer is not – not to use jpgs, but simply not to compress them too much, and submit them in a pixel or megapixel size which is adequate for the purpose.

 

Vector graphics don’t suffer from the matrix problem, but even so, wil pixelate in the end because they are composed of pixels.

 

However, sometimes, and it appears on that post above, there is a confusion between aliasing and pixellation. 

 

 Pixels are square because the hardware makes them square (they are actually simply mathematical points). So, like a brick wall, if you draw a horizontal line you can draw a pure edges line because the bricks all line up. Vertical likewise. But if you draw on a diagonal you have to go up in steps. Small steps but steps all the same. These jaggies are inevitable because we are viewing in pixels, and the effect is reduced by anti aliasing filters. However, at some degree of magnification the jaggies become visible.

 

If you want to use a bitmap and get rid of the pattern, just use a TIFF. You’ll still get aliasing – and always will, so long as you use pixels.

 

There is also another problem with vector graphics – many uploading sytems won’t accept graphic uploads by users other than in gif, png or jpg format. Nor above a certain file size, so you are back to compression and jaggies.

 

 

[TerrydParticipant @terryd72465]

Hi mgj,

 

after 29 years in the computer graphics business (with 18 years web design experience) I understand all you say, I just didn’t wish to get too technical for those who aren’t necessarily so informed as ourselves. 

 

I’m very puzzled by you assertion that ‘engineering drawings don’t have much fine detail’ in a previous incarnation as as a design draughtsman we were producing double A0 sheets with incredible detail.  I think that that we must differ on what is ‘detail’.  A photograph may have lots of colour detail but this is not the point I am making.  when I wish to enlarge a drawing to view small detail, fine dimensions and notes I need good clarity which is not what one gets with bitmaps anti aliased or not.  I too can provide raw files from my 12.3 mpixel equipment, with macro or celestial telephotos, but this was NOT what I was discussing. (My 1.00 metre continuous printer will also produce excellent photographic images from my files.)

 

I can appreciate the use of tiff format as a container for bitmaps, however when used in this way, i.e. as a container for jpeg compressed files they are rather large (something like 3 times the size of the original jpeg – depending on the level of jpeg compression of course.  I agree also that tiff are useful for vectors using vector based clipping formats, However size once again, can be a problem.

 

True vector formats will enlarge by a ratio of hundreds and still retain clarity despite the small amount of pixellation, which is not possible with any bitmap, anti aliased or not and the files will be much smaller than bitmaps by a substantial factor.  most model engineers will have graphics programs which will handle vectors so reading vector files should not be a great problem for most.

 

As far as internet use is concerned I think you misunderstood my suggestion, perhaps I did not make my point with sufficient clarity,  I was not suggesting that vectors should be used for web based graphics as I know that jpegs etc are the accepted formats, but rather as the best format for storing files for complex engineering drawings which can be downloaded, stored, enlarged and studied in detail.

 

By the way I also think that digital photographs will never surpass the quality of good analogue ones as the regular geometric array of pixels can never truly compete with the random arrays of molecular silver halides, in the same way that digital music recordings will never have the quality of analogue whatever the sampling rate.  Just my opinion (and experience).

[CirclipParticipant @circlip]

And don’t forget double efilump and aunty quarian Terry

 

   Regards  Ian.

[TerrydParticipant @terryd72465]

Posted by mgj on 23/04/2010 23:15:44:

With the greatest of respect, if you think I am going to be arsed to annotate a drawing, scan it, import it into Photoshop, convert it to vector graphics and then post it up on the internet – just so you can enlarge it so some fantastic size without it pixellating!

 

 

 

When I see such assertions I know that they mean exactly the opposite. In the same way that when I see IMHO I know that is exactly what is NOT meant. By the way I wasn’t suggesting that YOU should be arsed to do anything, merely making a suggestion to those less experienced who struggle to enlarge the small web sources we are often offered. 

 

I also find your tone when saying –“just so you can enlarge it without pixellation” quiet offensive.  You are suggesting that I am making these recommendations for a trivial reason.  You are quite wrong.  If I was not clear enough in my original posts about my reasons for my suggestions I apologise.  I may disagree with you and your viewpoint but will always try to respond politely.

 

I hope that you noticed that I also have a caps key!  Just because I don’t normally use it doesn’t mean I don’t have one, I just thought I’d prove it!

 

 

[mgjParticipant @mgj]

But Terry – we with such printers and scanners are the exception. Most are not working in that realm.

 

I can also accept that for full sized drawings (originals) are best generated as vector graphicsa, because size for size they are more compact.

 

As for detail – one can argue as one wishes, however a drawing tends to be one thing, and a photo tends to be another. I was comparing one with the other, and htere can be exceptions both ways.

 

We are not talking of storing originals. We are talking of a library of errors corrections and mods, generated, in the main not by draughtsmen with specialised systems, but by the average person with average programs and average equipment. Importantly the object is not to pass information about a whole system but in general a cnage to a small part of it.

 

So, one ought to be looking at what is needed to achieve that aim, and what most people are most likely to do  – not what a trained draughtsman with an interest in drawing is likely to do. So I reiterate, as a user of drawings, about the best you will get out of me, and I suspect the majority of others, will be an A41:1 scan annotated , probably by hand.  If you personally want that converted to vector graphics, by all means, and post it as such too. However such a conversion, in terms of function, will make not the slightest difference to the vast majority of users.

 

As for my attitude – that I am afraid is one of life’s little tragedies that you will have to live with, because I for one have absolutely no intention of finding, downloading, setting up and learning to use special or new and unfamiliar graphics platforms, which are, other than on the rarest occasion, going to be of not the slightest use to me.   For the ordinary modeler they would be no more than additional claggage on  an already fragmented hard drive.

 

All that approach would do is drive people away from the library – because plainly they are not going to be able to use it. 

 

In short, may I suggest you stop thinking like an expert  draughtsman, and start thinking like the majority of the “clientele” with whom you wish to communicate – some of whom, if you go back though the threads, can’t visualise a part from a plain 3 view.

 

That being so, its probably best if you communicate in a language with which they, not you, are familiar.

 

I’m glad by the way that you have found your find your caps key. That must be a great comfort.

 

 

 

 

 

 

[Dave HarrisParticipant @daveharris36943]

Keith,

 

         Just to say thanks for your explanation for allowing drawings to be sized for printing, I have now got A4 copies of the drawings I wanted

 

Dave

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