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ptc-1699471-Visitor
1-Visitor
March 27, 2014
Question

Is a model good enough?

  • March 27, 2014
  • 21 replies
  • 9539 views

Posted this a few days ago and not sure as to whether or not it went through, so trying one more time. This also piggy backs a little on the "should scale be removed" thread.

    21 replies

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    N
    nrollins2-Explorer
    2-Explorer
    March 27, 2014
    You mean this one?



    K
    kimndave91-Visitor
    1-Visitor
    March 27, 2014


    Thanks Nathan,



    That's it - https://xkcd.com/927/


    A perennial favorite.


    x

    N
    nrollins2-Explorer
    2-Explorer
    March 27, 2014
    This is an excellent point.

    robert.reifsnyder touched on this as well. I have actually passed up good
    shops that can do the work better, cheaper and quicker, just because they
    work from a 2D print and “I don’t have the time to make a fully dimensioned
    working drawing” (like I used to for every single part I designed
    ) I hate
    admitting that, but it is a fact. Moving toward an annotated 3D model and
    adopting that as the standard for developing manufacturable parts, will
    undoubtedly diminish my choices for capable shops. The ease of readability
    is key to success and efficiency in the whole process.



    And, Robert - Thanks for the LOTAR STEP AP242 standard lead. I am not
    surprised to learn of that today. I will check it out.



    And, David – I know you are not the only one who has found unparalleled
    success using PAPER archives when electronic media failed. I speak from
    first-hand experience as well. But don’t fear, Google likely has a solution
    for that coming soon.



    Good discussion. Thankfully I have time for it today.



    -Nate


    P
    ptc-280561-Visitor
    1-Visitor
    March 27, 2014
    I wonder if there is a way in the model to invoke a plane in the future?
    That plane would represent a sheet for the annotations.
    This might make it easier to read kinda like a drawing???

    Carl
    R
    RonGrabau1-Visitor
    1-Visitor
    March 27, 2014
    All,
    I am enjoying reading about this topic and everyone's emails. I think that this would be a great topic to discuss at the PTC Live conference. There is a Technical Committee that is dedicated to this subject. Perhaps we can get more insight from them. I will ping the TC chair and see if they can post any summaries. Here are the ramblings of an old man.

    I agree that I am somewhat old school in some of my thought processes. I cannot count the number of times that I thought I had a perfect drawing only to redline it as it came off the printer. There is something different seeing it on paper than on a computer screen. It may be my training and just how I think and see.

    I still think that many of our old practices are just that. Old practices that everyone is use to. I can remember people telling me that CAD will never replace the old board drawings. I also heard that 3D is just a toy and will never replace 2D. I think we are on the verge of making the type of changes being discussed below. I have several theories in life and I call this one I call the Egyptian theory. (Not that I have anything against Egyptian's it just that they created paper and started this whole drawing thing I am sure.) Once the paper drawing started, standards were created to make it consistent. (Scale is one of those items. You needed scales so people could buy scaled rulers to create lines and measure and fit on a sheet of paper.) Often the rules end up overriding the reason. There are rule makers and rule enforcers. The enforcers cannot change the rules they just make sure they are followed. The rule makers end up going away but the enforcers remain. Hence we are in the state of flat thinking.

    I have been wondering about all this for assemblies for a long time now. What is an assembly drawing? It is just a bunch of instructions. What are the components, how to they interrelate? Are there any special instructions (mark, torque, paint, stake, don't drop...)

    In the CAD world, a large assembly drawing can get cumbersome but by current reason are still necessary. We spend lots of time adding balloons, note callouts, sections, detailed views all just to describe what is this beast and what are its requirements? Most often, assembly drawings do little for the manufacturing build. Most manufacturing people make their own set of drawings detailing the steps to reach the conclusion that the drawing is trying to convey.

    On a drawing format you want to know bits of information. Model name, revision, change history, who to blame (signatures) general tolerance block, descriptive information about views and dimensions by specifying standards.

    I could go on, but I think I have made my point.

    It seems ludicrous that with all the technology we have we still have to record all of this on paper. I have PDM systems that track every revision. I have tools to verify what changed between every iteration. I know who created, who changed, who approved. I can automatically create paper or electronic versions. I have files that control materials, access specifications, generate notes and memo's. I can create light weight versions and put them on a device that I shake to get an exploded view. It is overwhelming the amount of information that I have and can share at my fingertips. Yet, I make a drawing using the same methods and standards as it was done with charcoal and pounded papyrus reeds.

    I agree with David on the fact that paper it probably the most reliable method for long term storage. Software vendors will only let you go back a number of versions. Operating systems change, media changes and some companies go out of business and there is no longer any way to get the data.

    Currently I don't have the answer to all of this. Yet I think we still need to push for new and better ways to document and convey what we want built and how it is to be done.


    Ronald B. Grabau
    HP PDE-IT
    Roseville, CA
    916-785-3298
    -<">mailto:->

    M
    mpeterson1-Visitor
    1-Visitor
    March 27, 2014
    With this idea about the plane of notes and Ron G's response (Egyptian theory) it got me wondering. Maybe we could create a "slab" part and then "engrave" the annotations in the slab to accompany the actual part. Then if a hard copy was needed it could be out put on a 3D printer.

    Just Kidding of course, well about the 3D printer part. It's Friday eve.

    Mark A. Peterson
    Design Engineer
    Varel International
    -



    T
    TimKnier1-Visitor
    1-Visitor
    March 27, 2014
    I do not dispute the fact that we can pack a 3D model full with all of the necessary information needed to make the part/assembly. However, before we crumple up all of our drawings and toss them in the garbage can, I think we need to consider the person that will be fabricating/assembling/inspecting the real world part/assembly. Do they have the necessary tools to extract all of the valuable information from the 3D model? Are those tools easy and accessible to use for this person in his/her working environment? If this person, ever, at anytime needs to write something down due to a lack of these tools, they've instantly justified the need for a drawing. I don't see a computer sitting next to every machining center on our shop floors. So it will be a while yet before we can eliminate drawings.

    Tim Knier
    QG Product & Support Engineering
    QuadTech
    A Subsidiary of Quad/Graphics
    Sussex, Wisconsin
    414-566-7439 phone
    -<">mailto:->
    www.quadtechworld.com<">http://www.quadtechworld.com>
    J
    japrenticeuk1-Visitor
    1-Visitor
    March 27, 2014
    I agree with the historical media problems and one might include serious IT
    stuff like ½” magnetic tapes too.



    I think the future is safer and from a superficially intangible medium – the
    Cloud. Server hardware will come and go but the worldwide investment in data
    “in” the Internet gives me hope that I can keep and access a very large
    stream of bits by a human understandable name (i.e. a file) for a very, very
    long time provided I curate it, verify its checksum and move it around the
    net as servers come and go.



    The challenge of whether those bits will mean anything is much bigger and
    here we might come full circle in the argument. PDF has a big enough
    presence to last – so I bet on the most recoverable design being in PDF
    files of conventional engineering drawings stored in public or private Cloud
    storage.



    John Prentice






    S
    sshannon1-Visitor
    1-Visitor
    March 28, 2014
    I read Johns comment and find myself thinking "Sure...but all it takes is one large micro-burst ...all my paper prints will still here."
    And that is not beyond the realm of possibilities. 😉
    D
    DeanLong1-Visitor
    1-Visitor
    March 31, 2014

    My .02....


    I have heard the buzz "drawingless environments" for 20 years or more. Many keep trying to make it all "cool and 22nd century" butfolks, remember, just because we "can do it" does not mean we "should do it" or it is the "best way to do it". Tim Knier has thecorrect thoughts on this thread in my opinion. This is not a technology question as much as it is a Human Being question. We simply do not operate well by interrogatingmanufacturing info on the screen when the rubber hits the road. It's really difficult to garner all the correct info in that manner. That is not how we operate or disseminate information in an optimum manner. We are not machines and we make mistakes.


    The big (eternal)issue is noteveryone "models" their parts in the exact same way those parts and assembliesmight bemanufactured or inspected. Ask yourself this question: Do you ALWAYS, 100% of the time, model your parts with the manufacturing AND inspection processin mind? Or better yet, once you know how the parts are going to be manufactured/inspected, do you go back and remodel your parts to mimic that methodology if your parts were not modeled that way in the first place? If you do not, then this thread is essentially pointless. In other words, you can't have it both ways. You cannot be lazy in modeling and then simply let the manufacturer figure it out.


    The reason we have "Arms length transactions" in things like real estate and legal matters is because we absolutely "need" the human element in the process to mitigate error. Sure, one could argue that the manufacturing/inspection process needs to usethe 3Dmodel to be correct because that is the "master". But, I submit it is better to create the 2D that explicitly states your intent as the product developer. For me, I choose to do the 2D when it ismission critical ensuring they get the full picture with less opportunity to get it wrong.


    Being an old timer, I consider the 3D only asthe lazy way to product. Too risky in my opinion.



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