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Three sides view of 2D (from 3D) projection

  1. Nov 12, 2006 #1
    Hi all

    I have searched on google already but couldn't find any good tutorials. Im talking about isometric projection from area (3D) to coordinate system (2D). Here is the ''easy'' example of the little house in 3D view CLICK and the same house in 2D view on coordinate system which is determinated with three side views CLICK2.

    I know I could do this in Pro Engineer but my ProE doesn't work :(.

    This example isn't so hard but I still need the tutorials and some tips because there are million of other much harder examples. Im trying to do those four articles:

    Article 1 and 2: CLICK3
    Article 3 and 4: CLICK4

    For example in article 3 (CLICK4 upper one) when i draw the ground plan, i need to separate the left part and the square. I know i need to mark the downer line of this left part with F kind of line - invisible (in SIST standard it is thin 0.1 mm with breaks, I think those breaks are 0.5 cm long) but I still don't understand how do I separate those two parts on the drawing?

    Does anyone know a good tutorial or any tips where I could learn this basic of technical documentation? Somehow, as ''our'' teacher on the faculty said, I need to know and understand this before I begin with drawing bolts, nuts, springs, shafts, seals, gears etc...
  2. jcsd
  3. Nov 12, 2006 #2


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    I know this is no direct answer, but any experience with the Monge projection would do good here. Did you have a descriptive geometry course or similar?

    In general, in such a drawing, if an object is 'beneath' the other one, you just draw things which could be seen 'through' the upper object with that 'F-kind' of line. You know that the object is beneath because you have other projections to confirm that.
  4. Nov 12, 2006 #3


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    Oh man. You really do need to spend some time on a real drawing board. You HAVE to get a grip on solid 2D projections. DO NOT become one of the monkeys that relies on PRO/E or CATIA or any other program to do your thinking for you. You need these skills. Your teacher is 100% correct. Consider this a very basic or fundamental skill. If you do not develop it, how will you expect to know what is going on with more complicated designs?

    Now, to your question
    When you say "ground plan" are you refering to the top view of the part? If so, neither of the segments of the part is square. If you explain what orientation you are using, we can answer the question.

  5. Nov 12, 2006 #4


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    Echo Fred.
    I have no idea how to use any of the programmes that people seem to rely on now. I do my draughting in Illustrator now that I don't have room for my draughting table/machine in my home. On paper, however, with a pencil and ruler, I could do all of those up within half an hour. It ain't rocket science.
  6. Nov 12, 2006 #5
    radou: Descriptive geometry course? Yes but Im not sure if this course (which is part of technical documentation) is the same here as in foreign countries. I call it '' computer aided drafting '' and the example of the task is HERE. I know, I opened the topic for a bit different reason but since you asked me about the course, I wanted to show you my course, which is similar I guess. In this task you need to find the cut (together point) between slanted three-side pyramid and area which is determinated by two tracks (three E points). When you find it in ground plan, you just move it to first side view - of course on the same line. The task of which I pleased for help is knowledge of the same course - it requires just one step higher understanding. I know the article might look easier to determinate as the task which I showed to you but I try to draw it, it isn't and thats why I pleased for any tips. Also I think I shouldn't draw everything with F line, it is just for invisible parts of the article. Other parts have other lines. I guess, in ground plan, I just put the left part of article on the rectangle and then show, in first side view, it is lifted for 82 mm.

    FredGarvin: Yes, I meant top view of the article. Here are orientations that I used HERE2 . As I have been told on ''my'' faculty, it is my own decision which side do I choose (of course NOT ground plan) for '' the first side '' and then the side which I didn't choose, I choose for the second side but as I heard there is one rule for first side view - Try to choose the side (again, NOT ground plan) where you can draw as few invisible margins / parts of the article as possible.
    Last edited: Nov 12, 2006
  7. Nov 12, 2006 #6
    Side question, are you studying to be an engineer or a draftsman?
  8. Nov 12, 2006 #7


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    Andreii, what you want is to learn to do third angle orthographic projections. Any standard text on Engineering/Technical/Machine Drawing will cover these in the early chapters.

    Do you not have an assigned textbook (or suggested reference) for this class?
  9. Nov 13, 2006 #8
    cyrusabdollahi: mechanical engineer. This is a part of mechanical engineering, at least here on our faculty.

    Gokul43201: I don't have it. Everything I have are two books with described drawing machine elements such as springs and shafts and one book with basics of computer aided drafting. There aren't explained projections :(
  10. Nov 13, 2006 #9


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    OK. I got it now. The "Z" bracket with two holes and a slot can be done very nicely with two views (top and front). Again, on either view, there is no square portion, only rectangles. The third part should have three views but could be done with two if some assumptions are made. If you want, perhaps we can walk through the view developments for these parts. I'll keep an eye out for more tutorials and such.

    The rule you mention for view selection is ok, but it's not the one I was taught or use to this day. To put it simply, it is the views that best describe the part as easily and quickly as possible. The important part is to pass along as much uselful information without wasting space. If it so happens that you get fewer hidden lines, then that works out even better because that would be much easier to read.
  11. Nov 13, 2006 #10
    They make you draw things by hand, outch. Don't worry, that will probably be the only class you waste your time drawing pictures in ever again. :!!)

    Is it ENES100? We did something like that too, only using Pro-E.

    Good engineers don't draw pictures to earn a living :wink:

    And if they do make a drawing, its not by hand.
    Last edited: Nov 13, 2006
  12. Nov 13, 2006 #11
    FredGarvin yes Thank you. I tried to draw the drawing of the article 3. I show the result. View of all three sides '' might '' be correct but I have no idea how to use exsactly those dimensions (as you will see in the link, I haven't marked the size of the ''lines'' yet) because, I remember, there is one majority rule which for my opinion ''deserves'' the bold letters:
    In all three sides, all widths and all lengths must be exsactly the same size. (I show on the drawing W as width and L as length).
    Location where I put the star - Im not sure how will I, with respect to dimensions, draw those two circles. Length between center of them is 70 mm. On the drawing I put 1 unit as 0.5 mm (for all dimensions of course), which means 70 / 2 but the width will never be the same as the one in first side view unless if I choose the dimension (in first side view) of both lifted parts. Similar problem I had in second side view. I wasn't able to make so small circles with compasses (radius 8, on my drawing 4).

    Here is the drawing CLICK
    In case if it isn't visible enough:
    Ground plan
    First side view
    Second side view

    cyrusabdollahi: ENES100? the book? Hmm no. They are Slovenian books (Im from Slovenia). When you mentoined ProE. Somehow, I finally got it fixed. When I opened this topic, I typed it doesn't work. Now, thanks God (because of more complicated drawings that will follow with full of bolts,...), it works. As FredGarvin told me - I need to understand those projections without ProE. However, Cyrusabdollahito, to be honest, I don't know anything about ProE yet. Im total beginner there :-( but Im interested in learning it and I hope as soon as possible. So, Im not able to do this in ProE (yet).
  13. Nov 13, 2006 #12
    Understanding projections is not rocket science, you will pick it up very fast.

    Drawing it by hand is nice, but I would not say it is vital (unless your a draftsman). You should learn PRO-E, here's why. I used pro-E in my ENES100 course, but its been about three years since I took it. Now I'm doing a heat transfer analysis and I am finding the temperature and flux distributions using, guess what, PRO-E. I had to have someone show me how to do it again, but I was back on PRO-E in about half an hour or so of relearning it.

    Had I draw things by hand in that class, I would have no clue how to use PRO-E.

    So, there are advantages to using software like Pro-E. (1) No respectable professor or company is going to accept hand drawings. (2) Hand drawings are outdated. If you want to see the object, make it in cad and rotate it with the mouse to see all the angles.

    But, don't sweat that stuff too much, its mostly dull and not engineering anyways. :wink:

    Learn powerful things like Matlab, Pro-E, Fluent, Nastran, and Ansis, so you can do REAL engineering analysis.
  14. Nov 14, 2006 #13


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    So, Cyrus... does this mean that you're going to buy me Autocad for my next birthday? :!!) :biggrin:

    I have no idea what the hell Pro-E is.
  15. Nov 14, 2006 #14
  16. Nov 14, 2006 #15


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    Great. More pretty pictures with colors. There's no mention that that design could be the most terrible thing to hit paper, but the pictures are pretty. That's the important part.

    I did not say that CAD packages were a bad thing or that people should not learn them or use them. I use one. Nor did I say that people still use hand drawings at their place of business. What I did say was to not become a brain dead monkey that sits in front of a tube and rely on the idiot box to do your thinking for you. If a person doesn't understand the basics of drawing by hand or 2D or whatever you want to call it, there is no way they are going to be able to interpret a drawing that PRO-E spits out at them. Draftsmen are a thing of the past. I have been an engineer for over 10 years and I have done my own drawings since day 1. So please stop pontificating as to what an engineer is until you become one yourself.
  17. Nov 14, 2006 #16
    Hmmm Im not trying to bother anyone, I just kindly asked for help. :confused:

    So side looks are correct I see, I just need to fix the dimensions somehow.
  18. Nov 14, 2006 #17
    I agree with you that you should know the theory and not simply click buttons. Im not saying there wont be times you have to make/interpret drawings, but if thats all you do, then no, your not an engineer. (not to you specific, im talking in general). That would be mere technical work. As for the comment on pretty pictures, how is drawing it by hand going to make any difference on if it is a good design or not?

    Learning all the methods of making projections by hand seems like a waste of time. We never did any of that, and I can see 2d projections just fine. It's not rocket science.

    Using the computer to draw pictures is not giong to make you lacking as an engineer. Were not talking about anything mathematical here. And learning to use something like CAD or PRO-E is a better use of your time because it acclimates you to other software that does mathematical analysis in the future.

    As for the being an engineer, I have been working an a lab for about 3 years now with engineers that are EE, ME, Physics, and out of all of them only one guy was ever drawing parts on a computer. The rest were doing computational analysis. REAL engineering. So I do know what good engineers do, and don't do. Drawing pictures by hand is NOT one of these things.

    Here is an example, in high school I was in the lab with the guys doing scramjet research. There was one guy who did all the drafting for the test rig (he was a draftsman), one guy worked the machine shop (he was a machinist), and one guy did facility work. As for the engineers, they did not do much hands on work unless they were setting up an experiment.
    Last edited: Nov 14, 2006
  19. Nov 14, 2006 #18
    cyrusabdollahi yes I know what you mean but on our mechanical engineering faculty, the teacher requires to draw the first ''basic'' drawings without programs but by hand... I remember from the previouns year, because I failed on this subject, I will have to draw some more complicated drawings by hand too. The teacher wants us to actually draw and not just using the program.
    So Im actually forced to listen him, otherwise he won't take a look at my homework / drawing.
    Thats why I don't search only for ProE tutorials but for explanation too.
  20. Nov 14, 2006 #19
    Does your school have access to PRO-E? If so and your course load is light, you should get a book and practice using it. You can become fairly good at it in about a week. It's really not hard, and a lot more fun than drawing pictures by hand.
  21. Nov 14, 2006 #20
    Yes, the staff of the faculty have their access to ProE. I have my too.
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