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Coordination process

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    Coordination process

    I am looking for some insight into how Structural Engineers handle the linked Architectural model, vis-a-vis the timing of a Shared Coordinate system being in place.

    Assuming the Architect has Shared Coordinates based on Civil before Structural starts work, what is the process that Structural uses for linking? Do you link Center to Center then Acquire Shared Coordinates? Or do you link Origin to Origin and then Acquire, so both the Revit Origin and Shared Coordinates match?

    Assuming that there is no Civil info until well into DD, would Structural link the Architectural model Center to Center or Origin to Origin, then Acquire Shared Coordinates later, when a lot of work has already been done? How much pain is caused on the Structural side if there is no Shared Coordinates until well into DD? Are you able to simply Acquire and keep rolling, or do we create heartache when we do this?

    The reality on our end (meaning my office and our school district clients, not Architects as a whole necessarily) is that we often don't have a good site survey until well into DD, especially if the site is generally flat and the site boundaries are well documented. We could just use a corner of the site for shared coordinates from the get go, but that can cause a different set of problems later when Civil and Landscape need the "real" coordinates. Just trying to understand the implications so I can help our PMs understand them as well.

    Pragmatic Praxis


    I think it depends, ideally if the location is settled as much as possible then we simply go by origin and acquire the co-ordinates.

    As a multi-discipline firm in many cases we will do both the civil and structural as we are getting further along we are actually incorporating lots of civil elements into our Revit models, and in this case our model is actually the location driving point for the Architect, it just makes it easier, notwithstanding adjustments that are made.

    Umm on some larger more complete projects things have moved quite significantly which I am always very hesitant to move, even though the old detail line not int he right plane is mostly fixed, i never tried doing massive shifts once we hit 75-80% unless the projects are small and it's easy to test them before overriding the existing location.

    I would say your plan of providing the location would cause no real issues for me, I would wait untill I got confirmation of the co-ordinates then incoporate them. However occasionally we have to provide pile, and foundation locations though generally this is left up to the contractor, based on the design.
    I would say those circumstances notwithstanding I would find it easier, especially in the earlier days when it's all guessing.

    I would also say check the ability of the engineer, we had issues with Architects not understanding the Revit co-ordinate system.



      There are no real implication on coordinate. You can create the model based on base point of 0,0,0 and move all the models to suit the site when the survey data is received.

      Flow this simple work flow and you should have no dramas.
      1-2 base on 0,0,0 coordinate system.
      1. Link the Arch Model into the Structural / MEP model via Origin to Origin, (there is no difference's between origin vs center to center if your model has not been create with out linking the arch model.

      2. Acquires coordinates from the Arch Model.
      Ensure that the Arch receives the Strut model and links in the Struct model via shared coordinates. Its import that the Arch links the structural model to create a relationship prior to moving the arch model.

      Survey Data received.

      3. Create a new model call IE Site. Link in the survey data (Center to center is used because the site is generally out of the 20mile limit). Move the Data to be in the Center of the screen. Find a datum point (this generally the survey point / mark of the survey) and specify the coordinates at the point IE 60050403,3034030,450.

      4. Link in the Arch model in to the Site model (Center to Center). Move the arch model to the required location. Move the Site model base to to match the arch model base point. Now Publish the Coordinate to the arch model. Save, a dialog box will ask you to save the position to the arch model, click save. Close the Site model.

      5. Open the Arch model and Save Close.

      6. Open the Strut model and reload the arch model. Re-acquire the coordinate from the arch model. This will move the coordinates to match the location on the site.

      This work flow can been done by the Strut and have the arch do the reverse.
      Simple tip alway move your model in site model and you will no issue with level and coordinates


      Dr Harry


        I have to agree with Harry on that one, that is essentially exactly how I do the process. I guess, it's always preferable to have that information done at the commencement of the linking process. That just gets all of that management stuff out of the way early on, and you can focus on just modelling rather than having to take time off from getting towards your final documentation and make adjustments. There are always little complications that require attention but things like that can usually be resolved early on.
        I guess this is where the entire co-ordination process should be questioned. If you are finding that you are needing to make this update regularly, perhaps you are taking (or handing over) the other consultant model too early in the process.
        I always prefer to see the architect model once the Design Development has been finalised. In an ideal world, the structure team wants the architect model when its finalised, and client has ticked all the boxes and doesnt want to make significant changes. Something as simple as moving a column for an architect, can cause a good half day of rework for a structural drafter, move the rebar, re-detail the rebar, change details, etc etc. So the more complete the model, the less re-work during documentation. That goes for the simple thing like co-ordinate also, as this means changing pages from true north to project north, changing north points in the project etc etc, all these things are minor (and would have to be done regardless of when in the project phase they happen) but the main point being they are generally handled easier right at the start before commencing any documenation at all...
        Thats just my 2 cents, and I know it sounds like utopia....


          This is a question that I continually have to revisit at project startup meetings, in the end no matter how you approach it you can make everything work together.

          But the ideal situation is the Architect sets the co-ordinate system both internal and shared (to match the survey base point) prior to the other consultants starting their models, then everyone else can link origin to origin, and acquire the survey co-ordinates. I know you dont need to all be using the same internal origin, but it just saves the headaches of dealing with additional shared co-ordinates on top of survey shared co-ordinates.

          But every time I mention this at startup meetings, everyone says "this isn't possible, we all just need to start something..." but all we need is a blank Revit file, with just a few grids to start from, something to ensure we all start from the same internal origin can save some additional co-ordination down the track, if we have survey great, if we don't we can add it later.

          But I think the real problem with setting up and combining models, is the process is something you have to understand, and when you do there is actually no real live feedback from Revit except when it works. With acquire co-ordinates for example, it just works or it doesn't. You get no dialog, nothing. Very difficult to explain to someone, whether its in your own team, or another consultant, its something that could be streamlined a lot better by Autodesk
          Revit BLOGGAGE


            Further reading, Mr Steve Stafford has just added a great write up to his BLOG on the ideal workflow for Architects to follow. Now I can just give Architects this URL!

            revitoped-Project Coordination - Early Days
            Revit BLOGGAGE



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