I can't deduce the third view of an engineering drawing

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Discussion Overview

The discussion revolves around the challenges of deducing a third view from two existing views in engineering drawing. Participants explore the algorithmic steps involved, the feasibility of constructing a third view, and the educational emphasis placed on this topic in their respective schools.

Discussion Character

  • Exploratory
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant seeks a general algorithm for producing a third view from two existing views, expressing frustration with the lack of attention to this topic in literature.
  • Another participant questions the feasibility of always being able to deduce a third view, asking for examples where this has been successfully done.
  • Some participants argue that each of the three views contains unique information, suggesting that two views may not always suffice to construct the third view.
  • There is mention of a "removed view," with requests for clarification on what this term means in the context of the discussion.
  • One participant references a book that discusses projecting a third view using a 3D isometric view, while others note that this method may not apply in all cases.
  • Concerns are raised about the assumptions made when deducing the third view, particularly in cases where both views are identical shapes, leading to ambiguity regarding the object's true form.
  • Some participants draw parallels between the problem of deducing a third view and projecting points or lines, noting the limitations of such projections.
  • There is acknowledgment that the topic is essential in the educational context of some participants, with a whole chapter dedicated to it in their curriculum.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of deducing a third view from two existing views. While some believe it is possible under certain conditions, others argue that it is not always achievable, indicating a lack of consensus on the topic.

Contextual Notes

Participants highlight limitations in their understanding and the definitions of terms like "removed view." There is also mention of specific educational practices that may not align with broader theoretical discussions.

AhmedHesham
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Hi
What are the general algorithmic steps of producing a third view from existing two. I can't do it for all cases. So I am searching for an algorithm to follow.
Famous books don't pay a lot of attention to the subject. But in my school it is ! Can someone please help me with the steps. And by the way I believe in my mental ablities so don't say the problem within me. I believe everyone can do it!
 
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AhmedHesham said:
I can't do it for all cases.
Are you sure it can be done at all? Can you show some cases where you have been able to do it?

http://getdrawings.com/img2/3-views-of-isometric-drawing-52.jpg

1582218811243.png
 
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AhmedHesham said:
I can visualize this
No, my point is that there is information in each of the 3 views, and for some objects, you need all 3 views to understand the part. If you only have 2 views, then I don't think you can say that you will always be able to construct the 3rd view.
 
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berkeman said:
No, my point is that there is information in each of the 3 views, and for some objects, you need all 3 views to understand the part. If you only have 2 views, then I don't think you can say that you will always be able to construct the 3rd view.
In some books I read there is a removed view that you want to deduce and construct and in my school there a whole chapter dedicated to the subject I know it's not that interesting and not important but my dang school want it.
 
AhmedHesham said:
there is a removed view that you want to deduce and construct
Can you attach a file with a couple of drawings? I'm not sure that I understand what you mean by "removed view". Do you mean modifying a view to show a portion of a part removed?
 
berkeman said:
Can you attach a file with a couple of drawings? I'm not sure that I understand what you mean by "removed view". Do you mean modifying a view to show a portion of a part removed?
In a book named technical drawing for engineering graphics there is a portion named projecting a third view in which he does it and construct a third view from two with the help of the 3d isometric but in my school we do it without the isometric check the book if you can
 
AhmedHesham said:
construct a third view from two with the help of the 3d isometric
That's going to help a lot having the isometric view (not in all cases, depending on the perspective of the iso view).

I don't have your book. What is a "removed view"?
 
No I really mean it
Deduce a third view from available two views
 
  • #10
The book of my school is in Arabic I can't upload it
 
  • #11
As others have said and also in other threads (search "orthographic") it is impossible in some cases. Consider two views which are both just a rectangle: the object could be a cuboid, a triangular prism or a cylinder, at least.
I suppose that if you are given only two views, the assumption must be that all significant features are visible and the third view is the simplest possible that is compatible with the other two.

Would it help to see a suggested procedure for developing the third view of, say Berkeman's drawing?.
 
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  • #12
Merlin3189 said:
As others have said and also in other threads (search "orthographic") it is impossible in some cases. Consider two views which are both just a rectangle: the object could be a cuboid, a triangular prism or a cylinder, at least.
I suppose that if you are given only two views, the assumption must be that all significant features are visible and the third view is the simplest possible that is compatible with the other two.

Would it help to see a suggested procedure for developing the third view of, say Berkeman's drawing?.
I agree with you
But it may be like constructing the projections of a point... If you have two the third projection of the point is completely specified.
It's actually essential in my school... A whole chapter is dedicated to it.
 
  • #13
It works for a point. But a line is a collection of points for which you can only definietly match the end points. There is no way of projecting individual points on the line, except the ends, because you don't know where they are.
 
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  • #14
Merlin3189 said:
It works for a point. But a line is a collection of points for which you can only definietly match the end points. There is no way of projecting individual points on the line, except the ends, because you don't know where they are.
Yes that's exactly the problem
But how can you explain that my school made a whole chapter for it and that they will be in the exam.
 

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