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Yay for CAD!

  1. Mar 28, 2006 #1

    siddharth

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    I just had a torrid time in my manual drafting class. It was a complete disaster! After projecting the whole drawing on the chart, I found that I made a mistake in my first projection, as a result of which the whole thing was wrong.

    The engineers who drew technical drawings using manual drafters before the advent of computers, must have been really skillful and must have had bucket loads of patience. You truly appreciate the power of CAD after attempting a complex manual drawing.
     
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  3. Mar 28, 2006 #2

    Evo

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    This reminds me of when a friend of mine spent countless hours doing a rendering for an architecural project which also included trees outside the building. Something went wrong and all the trees fell over mid trunk and it looked like a hurricane had gone through and knocked them all over. I thought it was hysterical. He didn't. :redface:
     
  4. Mar 28, 2006 #3

    brewnog

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    Sid, a well practiced draughtsmen will always have made a sketch of his drawing before he started the drawing. That way, when you're doing all the painstaking detailing, you're essentially copying from something you know to be correct.

    Can't remember what the rhyme was, something about "a quick sketch or something saves projections drawn in vain", but was catchier and rhymed. :smile:
     
  5. Mar 28, 2006 #4

    FredGarvin

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    I'm borderline looking for my soapbox...Sid, I'm glad that you have an appreciation for what it takes to do a proper drawing. It is a talent.
     
  6. Mar 28, 2006 #5

    PerennialII

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    .... at times when get error messages having for example "15 numerals" followed by something referring to for example "geometry corruption" feel like manual drawing may have its merits :biggrin: .
     
  7. Mar 28, 2006 #6

    Danger

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    I really miss my home-made draughting table with the machine and compass set. It's still around, but no place to put it. Can't afford CAD, so I have to do my mechanical drawings in Illustrator. Just to feel more comfortable, I drew and grouped a draughting machine that I can manipulate and lock down on the 'page'. It's redundant, but more familiar than just specifying lengths and angles. :approve:
     
  8. Mar 28, 2006 #7

    russ_watters

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    People still teach that? Why? :confused:
     
  9. Mar 28, 2006 #8

    Astronuc

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    Tradition! :biggrin: :rolleyes:

    I remember drafting before computers - AAARRRGGGHHH! I have great respect for drafters, especially those who had to do complicated structures or designs. :approve:

    CAD has certainly made it easier, but nevertheless, it is still challenging based on what I see people do in the office where I work.
     
  10. Mar 28, 2006 #9

    Gokul43201

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    I loved drafting by hand...especially the non-trivial problems involving just planes and lines (not parts of a solid/machine part/assembly). What fun !

    I miss Engg. drawing. CAD's no fun at all !
     
  11. Mar 28, 2006 #10

    brewnog

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    My university was the last in the UK to still teach manual drawing alongside CAD. I loved it, you feel a proper sense of achievement when you can give your drawing to some dude in return for him giving you your part a few days later!

    One of the time served Cad Monkeys (as was draughtmen) at my work retired last week, a boring old sod he was. Anyway, he was forever banging on to me about how, when he was able to buy a variable-angle set square, he was over the moon and throught it to be the best labour saving invention ever. You should have heard how he descried the day he bought his first electronic calculator!
     
  12. Mar 28, 2006 #11

    FredGarvin

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    I think I am one of the only people left that will argue that point until my dying breath. Being able to do proper drawings, by hand, is a teaching process to get people to visualize the parts/things they are working on. I think it's incredibly important for all technical people to know what is involved in making a proper view of an object. Once you have that, understanding a print is much much easier, not only for you but for the others that you are trying to convey information to.

    Modern CAD packages are wonderful, but like math, one HAS to know how the idiot box came up with the answer. If you can't draw it by hand, you don't truly understand it. Of course that's just my opinion. I may be wrong.
     
    Last edited: Mar 28, 2006
  13. Mar 28, 2006 #12

    FredGarvin

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    Ahhh...descriptive geometry. I liked that too.
     
  14. Mar 28, 2006 #13

    enigma

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    You're not wrong. The class I took which taught me to draft started off with 3 months of board drafting followed by 9 months of CAD. You need to know what linetypes, linethicknesses, etc. mean if you want to do a professional drawing. Period.

    I've re-trained too many people who 'knew CAD' but didn't know how to draft. It's frustrating.

    Still... board drafting does bite the big one.

    To quote my old boss: "Never draft in the morning what you can't erase in the afternoon"
     
  15. Mar 28, 2006 #14
    Drafting, programming. Drafting, programming............hmmmm which do I hate more? :confused:
     
  16. Mar 28, 2006 #15

    Moonbear

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    From the post that started the thread, I'd say it's taught so you learn to be careful not to make small, but disastrous, mistakes. :biggrin:
     
  17. Mar 29, 2006 #16

    FredGarvin

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    That is true. If I could only do that in other areas too.
     
  18. Mar 29, 2006 #17

    brewnog

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    Another pro-drawing anecdote:

    The guy who employed me, also a time-served type of chap, is adamant that the best Cad Monkeys he has ever employed have all got at least a basic drawing board background. Even if you're just sketching an idea in a meeting, it's much easier to get your idea across if you can do basic projections. I'm no artist (some of you have seen my uploaded graphics!) but I'm pretty shed hot for someone my age with the old parallel motion, and it makes visualising parts prior to modelling them a piece of wee.
     
  19. Mar 29, 2006 #18
    CAD operators who lack board experience, have what I call tunnel vision (limited view of the whole drawing). For example, a CAD person drawing four pipes and labeling them will frequently show the pipes turn a corner and miss label the pipes on the other side.

    They also lack a feel for the rises and falls of a structure. When board drafting, drawing a line that crosses a change in elevation such as a pipe or duct running along at one height and hitting a rise in a ceiling elevation, requires the draftsperson to physically extend that line with their pencil or ink tool, going from that corridor to that gymnasium and they notice this requires at least some thought. A CAD person connects the dots and has no feel for the actual route being followed. This is compounded by tunnel vision (they see only part of the picture). You end up with a duct popping through a wall and running across a gym at ten feet over the floor instead of twenty feet above it, resulting in a big extra cost to add that rise and those two elbows.

    In defense of CAD, it is a remarkable tool when combined with good drafting techniques. Duplication of objects and lines, creation of angles, lettering, creating elevations and projections are incredibly easy and accurate with this tool.

    The odd thing is again, if you've never done it by hand, the real power of the tool is often overlooked. I've seen CAD operators draw the same detail twenty times on a drawing rather than create a block copy, or at least just window copy the area! I've seen them draw identical duct systems in multiple rooms of buildings like schools rather than copy them! Or fill in line after line of identical text rather than do a multicopy. And they do it because they don't know that every time you draw something, you are taking a chance on drawing it wrong.

    Draw it once, check it twice, and copy it every chance you get.
     
  20. Mar 29, 2006 #19

    FredGarvin

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    I think everyone who uses a cad machine should be able to bisect an angle or create a polygon using a compass. If they can't then they can't appreciate what a lifesaver cad packages are.

    Still, there's a certain enjoyment from doing it by hand. Sort of like doing a hard jigsaw puzzle or a long project of some kind.

    As a side note, I have always worked in 2D with AutoCAD and Solids with Pro/E. I have spent the last 2 weeks working on revising old prints in 2D and I have really enjoyed it. I will be the first to admit that working in solids makes you lazy when it comes to drafting skills. The 2D keeps me going with the actual laying out of lines. However, the solid work helps me to think of the poor schmucks in the machine shop who get to make my master pieces. I like using them both.
     
  21. Mar 29, 2006 #20

    Moonbear

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    I just love the way the British speak. I'm not exactly sure what that last sentence says, but it sounds like all you have left to do is roll over and have a cigarette. :rofl:
     
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