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    Linked CAD file in a linked Revit file

    Hi,

    I'm in a process of writing a Revit manual for my office and I'd like to know your opinion on the best practices of CAD file linking.
    I know that some people are using a linked Revit file as a container for all CAD links.
    It does sounds like a great idea, but I'm not sure how would this work for sections or elevations.

    I'd really appreciate your feedback.

    Kind Regards,

    Maciej
    Maciej Wypych

    Bibere humanum est, ergo bibamus!

    #2
    We discourage linking AutoCAD files. If it unavoidable we will do it but if it is more than one or two files then something is wrong with our approach to the project. I can't think of any reason why we would want to link AutoCAD files into elevations and sections. It's not the right way to do things, IMO.

    Probably not the opinion you're looking for and others may disagree but our approach is to do Revit projects with Revit links and leave AutoCAD in the box, if we can.

    Comment


      #3
      Hi,

      I agree. This will be ideal world scenario.
      But so far, if you work on an exiting building and you need to model elevations, you'll need to link a CAD survey (at least for the modelling stage)
      Or if you have a consultant using only AutoCAD and you want to check his design against the model, I don't see any other way.

      I know, I know you can use point clouds for surveys (I've used them so far on a few large projects only - it's a bit expensive for some clients), or have a Revit survey model (almost never happens and the quality is usually er...hmm..*^%$##....:banghead: ) and use different consultants - but unfortunately it's not always your choice.

      So it seems that CAD links unfortunately will be there for a while, and I would like to make sure that they won't mess our projects.



      At the moment I've got so far:

      1. NEVER import CAD files into a project.
      2. Link CAD files only if necessary, for reference only.
      3. Remove links as soon as the information is modeled/checked/approved
      4. Link the CAD file to a specific workset. Refer to manual for workset naming.
      5. Use shared coordinates if possible - if in doubt ask model manager
      6 To prepare the CAD file:

      Use OVERKILL command in AutoCAD to remove duplicate linework
      Bind xref's, explode and purge the drawing
      Delete unnecessary lines, purge and audit the drawing
      Set all properties to "By Layer"

      Thanks,

      Maciej

      (Sorry for my rant. I need more coffee)
      Maciej Wypych

      Bibere humanum est, ergo bibamus!

      Comment


        #4
        Originally posted by maciejwypych View Post
        At the moment I've got so far:

        1. NEVER import CAD files into a project.
        2. Link CAD files only if necessary, for reference only.
        3. Remove links as soon as the information is modeled/checked/approved
        4. Link the CAD file to a specific workset. Refer to manual for workset naming.
        5. Use shared coordinates if possible - if in doubt ask model manager
        6 To prepare the CAD file:

        Use OVERKILL command in AutoCAD to remove duplicate linework
        Bind xref's, explode and purge the drawing
        Delete unnecessary lines, purge and audit the drawing
        Set all properties to "By Layer"

        Thanks,

        Maciej

        (Sorry for my rant. I need more coffee)
        coffee? It's :wine: time here I'm a subcontractor so on any project that the Architect has not produced a Revit model I'm reduced to using Acad links as backgrounds. Regarding
        #1: I agree 100%
        #2: I agree 100%
        #3: I can't remove the links in my projects, they are my building backgrounds. So far, no problems. :hide:
        #4: I agree 100%
        #5: I agree 100% as the model manager
        #6: I agree with all of your process, the only thing that I would add is I convert all content in the CAD file to layer 0 unless I have to manipulate visibility in my Revit model for some reason.

        Someday everyone will be using Revit (or whatever is next) but unfortunately it won't happen in my business lifetime. So, I figure out how to deal with the AutoCAD stragglers...

        btw, as a matter of kudos, I learned most all of the above process from posts by Aaron Maller over the years here. Stuff that I would have never thought about, he thinks about.
        I'm retired, if you don't like it, go around!

        Comment


          #5
          apologies for necro'ing an old thread, but i know the topic has been done to death so didn't want to add a new one into the mix.

          a few colleagues with autocad knowledge greater than mine have expressed some concerns over our CAD clean up process which currently involves binding xrefs and exploding everything multiple times. the concerns seem to largely stem from block definitions or layer properties somehow becoming convoluted, exploding "makes a mess of everything", and additional meaningless text/attribute definitions appear when things are exploded.

          i was always taught that it's better to bind and explode to expose everything, then overkill/purge/audit. then feel free to wblock or copybase+pasteorig into clean file as an extra measure.

          is there a general consensus here on the cleanup process or any reasons to leave certain commands as a last resort only? any ways to alleviate some of the concerns (i.e. fixing properties to ByLayer)?

          Comment


            #6
            Technically, you want most of the elements in your AutoCAD block to be ByBlock, not ByLayer (just allows you to change the properties of a one-off block if you need) -- regardless, I wouldn't make it a standard to bind (as link or as insert) and explode the bejesus out of the file. Too many bad habits in AutoCAD blocks that throw things on weird layers to make that a standard in my eyes. I'd rather not bind either -- it just means I have to do it all over again when I get the next file. Either my consultant does it, or I'd link multiple files (assuming we're not talking about a crazy number of links).

            What I'm really pushing for these days, however, is a rasterized PDF instead of a DWG.
            Greg McDowell Jr
            about.me/GMcDowellJr

            Comment


              #7
              So is the major concern with exploding blocks just that the exploded lines end up on unusual layers? If all block elements were set to ByBlock prior to exploding would this not go a large way to preventing the issues?

              On the flip side, what are the drawbacks to leaving blocks as they are and linking into Revit?

              Comment


                #8
                Originally posted by GMcDowellJr View Post
                Technically, you want most of the elements in your AutoCAD block to be ByBlock, not ByLayer (just allows you to change the properties of a one-off block if you need) -- regardless, I wouldn't make it a standard to bind (as link or as insert) and explode the bejesus out of the file. Too many bad habits in AutoCAD blocks that throw things on weird layers to make that a standard in my eyes. I'd rather not bind either -- it just means I have to do it all over again when I get the next file. Either my consultant does it, or I'd link multiple files (assuming we're not talking about a crazy number of links).

                What I'm really pushing for these days, however, is a rasterized PDF instead of a DWG.
                Why rasterized, when we have the new functionality of being able to snap to elements in a vector-based PDF?

                Comment


                  #9
                  What new functionality you have doesnt actually snap to Vector. The PDF is rasterized and THEN snapped to, on link/import, regardless. Its awful.

                  Youd be crazy to snap to either a PDF or a CAD file, if you cared about your project.

                  That said, i do very little, to clean up CAD files, unless there is a problem the CAD file is causing. IF i am linking in a cad file at all, its generally a temporary reference. If i absolutely need one for a final deliverable (like Civil), ill wait until the 11th hour, then spin off a cleaned up version. I wont bother exploding everything unless there is a far off element that seems to be enclosed in a Block, but in those cases i will.
                  Aaron "selfish AND petulant" Maller |P A R A L L A X T E A M | Practice Technology Implementation
                  @Web | @Twitter | @LinkedIn | @Email

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