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Revit - The Curious Case of Disappearing Dimensions

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    Revit - The Curious Case of Disappearing Dimensions

    Revit - The Curious Case of Disappearing Dimensions

    I just wanted to point out that Revit is great at propagating "changes" but sucks when it propagates deletion to detail objects.

    When someone draws a detail plan, there a hundreds of dimensions in rooms and other places which get "automagically deleted" if they happen to reference something that is no longer there or was deleted and added again later.

    Would it be possible for these Dimensions to become "unreferenced" and display an attention sign but still display the old data?
    It is a heck of a lot harder to spot the missing information when the old information is no longer there, and to top things off... you typically find out when printing.

    #2
    Revit doesn't really have a "Dimension"
    Just like a Tag, a Dimension in Revit is a tiny database report.
    It's just showing you the values of modeled objects.
    If an object isn't there anymore, how could Revit report on it?

    Even if it did, what happens when you ad that object back in later? Does the orphaned Dimension somehow magically know and replace itself?
    Even if you could get this "working", what do you do when you really DO want to delete something? I think you're going to end up with a lot more orphaned dimension that you don't want than missing dimensions that you need to replace later.

    That's just the way Revit is. It's real. If you delete something, it's gone.
    Yes, there are some coordination issues. They're just different coordination issues than you're used to.
    Dave Plumb
    BWBR Architects; St Paul, MN

    CADsplaining: When a BIM rookie tells you how you should have done something.

    Comment


      #3
      While I understand the technical limitations, Revit is advertised as being "the way architects think". I do appreciate the dynamic nature of Revit, but as an Architect myself on a big project with over 160 sheets on file I beg to differ, I don't think that way. No one in my office does. In my mind dimensions don't just disappear, in fact... it is my mind that expects a dimension to be there and Revit feels otherwise.

      This is an issue, not a major disaster as we can cope with it, but it is getting rather tiresome to constantly find missing dimensions that people swore they put in. In time it creates an eerie feeling of uncertainty about Revit retaining the data we put in. Constant checkup is not the solution, if Revit starts to aggravate me the same way my wild son does then it's all over.

      That said, I've seen databases that have a kind of history in them, a ghost wall of some kind could be retained in the model to signify that there are some elements tied to it. It could ask the draftsman to select the ghost wall, and then list all the dimensions that refer to it and then case by case ask for a different reference *fix* to be specified. This would be a hell of a lot better than a list like it has now, before i make a change, telling me that this and that will be deleted. It doesn't understand that "I need to make the change" and software is there to help me do that, not give me a myriad of reasons why I shouldn't move a wall.

      Knowing Autodesk's history i doubt this will ever be implemented, it's so basic that if the original designers didn't put it in Autodesk will never go back and change it. "It just doesn't work that way" will be Autodesk new motto, and in 10-15 years, Revit will be the "new" Autocad.

      Originally posted by DaveP View Post
      Revit doesn't really have a "Dimension"
      Just like a Tag, a Dimension in Revit is a tiny database report.
      It's just showing you the values of modeled objects.
      If an object isn't there anymore, how could Revit report on it?

      Even if it did, what happens when you ad that object back in later? Does the orphaned Dimension somehow magically know and replace itself?
      Even if you could get this "working", what do you do when you really DO want to delete something? I think you're going to end up with a lot more orphaned dimension that you don't want than missing dimensions that you need to replace later.

      That's just the way Revit is. It's real. If you delete something, it's gone.
      Yes, there are some coordination issues. They're just different coordination issues than you're used to.

      Comment


        #4
        That's how it is though. If you reference an object with a dimension and you delete it, you'll delete the dimension (and tags etc) along with it. You can move the wall and the dimension will adapt. If you delete the wall, it won't. It can't dimension something that isn't there.

        You can make a lot of reference planes, lock them to your walls and dimension to all the reference planes instead, which would keep the dimensions when you delete the walls, but I wouldn't recommend that workflow.

        Just as a personal opinion, Revit does work in the same way that I think. I've never really used AutoCAD so I was never in that mindset, but I can't imagine the use in the way I work to have a dimension remain that doesn't link to anything when I delete a wall.
        Last edited by Cyus; January 17, 2014, 03:43 PM.
        "I WANT SOUP! This fork is useless! I'm going to use my spoon for everything."

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          #5
          Originally posted by basilmir View Post
          as an Architect myself on a big project with over 160 sheets on file I beg to differ, I don't think that way. No one in my office does. In my mind dimensions don't just disappear, in fact... it is my mind that expects a dimension to be there and Revit feels otherwise.
          Quoted so I can get back to this later..

          Comment


            #6
            Originally posted by basilmir View Post
            While I understand the technical limitations, Revit is advertised as being "the way architects think". ...
            If you use marketing spin to base your expectations on you will oft find yourself upset in life, let alone Revit. You are asking something analogous to keeping the love-life after a divirce if you expect a dimension to dimension something no longer in existence...

            Also remember the marketing spin that you cite "Revit is advertised as being "the way architects think"" If you cannot see that a blanket statement is impossible to be accurate and can not realistically include everyone; since we all think differently from one another; then you should really re-evaluate what you choose to believe.

            Revit does only that which we tell it...it's software and has to be used as it works, while we keep pushing the developers to make it work how 'we' want it to, we must all remember: there are thousands of "we" at play!!!
            -J
            http://about.me/JayZallan
            Tweet, Link or Blog me up!!!

            Comment


              #7
              Revit doesn't delete entire dimension strings. If you use a dimension string and one object gets deleted the entire dimension does not go away, only the piece to that part gets removed. try it out place a number of diff. objects, dimension them, then delete one of them, only the object that got deleted goes away, so if you then put a new object in its place you highlight the dim string and click the edit witness line and add the new object to the string. Works exactly how you would want, except you want it to leave a mysterious dim to nowhere until you come back to the area, either way you have to correct the dim.
              Scott D. Brown, AIA | Senior Project Manager | Beck Group

              Comment


                #8
                Originally posted by Basilmir
                ..."It just doesn't work that way" will be Autodesk new motto, and in 10-15 years, Revit will be the "new" Autocad...
                Seems to me that the fastest way to make Revit like AutoCAD is to leave dimensions behind when their related elements are gone. That would be like AutoCAD before Associative Dimensioning was introduced. When was that? Around r12? Earlier?

                When someone is examining documents a dimension that has gone missing will be likely to generate a request for information (RFI). A dimension that is not deleted but referencing something incorrectly could lead to a mistake in construction which in turn could lead to a change order.

                I'd rather deal with an RFI (earlier) than have to authorize a change order (later). Unfortunately some situations might cause both, an RFI and then a change order to resolve it all. Since I spent many years on the fabrication side of things I'm always worried about sending a drawing into the shop to make hundreds or thousands of parts. It will be very costly if those improperly referenced dimensions are lingering behind and as a result negatively affect my shop drawing(s) when they shouldn't.

                Revit depends on us to define dimensioned relationships correctly. We can reduce how many dimensions are deleted if we are careful to make sure they reference the element we intend them to. Dimensioning is not just a click here and there, dull or tedious exercise we have to do. Sometimes it seems as though that's how it is approached. These are just three examples:
                • Imagine a dimension that is referencing the edge of a Wall when the intended element was a Grid. If the wall goes away then the dimension will too. I meant to dimension to the grid but since both elements were overlapping or very near one another I didn't notice the wall got the dimension reference instead. It happens all the time. Watching the status bar (and tooltips) is important because it is there that Revit shows us what the dimension tool sees.

                • Families that are built without consistent IsReference settings cannot be swapped out properly because one family may not define anything a dimension can reference. For example, if two desk families have a reference plane on the right side but one is assigned to IsReference: Right and the other is set to Not a Reference, a dimension placed referencing the right side of the desk will be deleted if the desk is swapped for the other one using Not a Reference.

                • Linked files can be changed but not reloaded prior to using Synchronize with Central (SwC) and when that happens a paradox of sorts occurs. Revit attempts to resolve dimensions that are related to elements in a linked file but changes in that file were not reloaded (by other users yet) and saved first. When the SwC finishes it does not find the linked file's referenced elements and a warning is generated telling us that dimensions were deleted. If we reload linked files first (those that are seeing ongoing changes during the day) and then use SwC we can reduce or eliminate the number of times this occurs. It is my habit to reload linked files first so any changes (that I am unaware of) in them are captured in my local file. Once I deal with any warnings related to those I can use SwC with a much higher degree of confidence
                Last edited by Steve_Stafford; January 17, 2014, 05:06 PM.

                Comment


                  #9
                  You're not thinking this through all the way. The last thing I want is a plan with a bunch of dimensions that reference things that aren't there.

                  Comment


                    #10
                    Originally posted by need4mospd View Post
                    You're not thinking this through all the way. The last thing I want is a plan with a bunch of dimensions that reference things that aren't there.
                    That's the reason this would be a really dangerous function. I rather have missing Information then wrong Information. The financial impact of a missing dimension, most likely will be a drawing revision. A wrong dimension being build can become a financial disaster.
                    Ewoud Ruifrok
                    Building Information Manager

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