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Duct bends not being drawn in when I try to automatically connect the ducting

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    Duct bends not being drawn in when I try to automatically connect the ducting

    Hi,

    I am using Revit 2017.

    I am trying to connect a duct from a shoe to another existing duct which has a different offset but the bends are not drawing in.
    The offset of the shoe is -250mm and the offset of the duct is -750mm.

    I go into the “Systems” tab, and in the “HVAC” panel, I select the “Duct” button. I click onto the centre of the shoe face, and in the “Modify|Place Duct” contextual tab, I select the “Automatically connect” button. I then click onto the centre of the existing duct and the duct is drawn straight. A message comes up saying, “There was not enough room to place the required fittings. Consider increasing the length of the segments, or moving them farther apart to generate a solution.”, where there is plenty of space between the points, say, 1000mm distance horizontally.

    Many thanks. Tim. :banghead:
    Tim Stretton ¦ AutoCAD MEP 2D & 3D & Autodesk Revit.
    (Used AutoCAD since release 12 & 13 in 1996. Learning Autodesk Revit, not BIM yet)
    “Eppur si Muove! (It [the Earth] still moves!)” —— Galileo Galilei (15-05-1564 › 08-01-1642)

    #2
    It’s okay now. I just needed to lower the duct from offset -750mm to offset -1000mmm. Done!
    Tim Stretton ¦ AutoCAD MEP 2D & 3D & Autodesk Revit.
    (Used AutoCAD since release 12 & 13 in 1996. Learning Autodesk Revit, not BIM yet)
    “Eppur si Muove! (It [the Earth] still moves!)” —— Galileo Galilei (15-05-1564 › 08-01-1642)

    Comment


      #3
      Probably will need to run this duct in a Section view so you can manually run the rise/drop offset. Or, use an actual offset fitting and manually set the value.

      While in plan view, if one point of duct is at a different elevation than another point of duct, Revit can't figure out the right path of offset to connect between the two, thus causing the error. So, manually routing the duct in a Section View is the best method when you're routing duct.

      -TZ
      Tannar Z. Frampton ™
      Frampton & Associates, Inc.

      Comment


        #4
        Yeah ducts are annoying. I recommend the following:

        1) check your Routing Preferences (Select a duct, do Edit Type). Make sure you have all the types of fittings defined and families that work. Check it is not automatically trying to make a T, because the shoe will be automatically regenerated using whatever is in the routing preferences when you connect the ducts.

        2) when modelling ducts and pipes, dont think about the fittings.. just make sure the ducts and pipes are in the right place and connect them with Trim or Connect Into. Its better to let revit do its thing with fittings, just make sure they are set up properly. Note that using trim on ducts at different heights has different results depending on which duct you click first..

        3) Revit doesnt like; Limited space, give it lots of room to make the connection then move things closer. Slight differences in angles or heights, keep everything neatly lined up and perpendicular where possible, use Align to line things up if you are not sure. Ducts that have been rotated around their axis (Never draw ducts in a section view, where Height and Width are switched!! Draw vertical ducts in plan or 3D by changing offset).

        4) Dont use Justify, it sucks and makes everything more difficult... To make Eccentric connections use this trick; Use Split near the end of Duct A to insert a Union. Delete the last bit of duct so that the union is on the end of the duct. Select the union, do Connect Into and select Duct B.

        5) If something doesnt work, there is often 2 or 3 other ways to try and do it. Revit is stupid but usually provides several stupid options to try....
        "One must imagine Sisyphus happy." Albert Camus - "The innovator has for enemies all those who have done well under the old conditions, and lukewarm defenders in those who may ​do well under the new." Nicolo Machiavelli -"Things that are too complex are not useful, Things that are useful are simple." Mikhail Kalashnikov

        Comment


          #5
          Draw from the end of the duct in plan, change the offset to the offset of the second duct, keep drawing in plan. Revit will make the height offset if it can. Then connect into the second duct.

          If you MUST model in a section.. select a horizontal duct, Copy and Rotate, Trim. Otherwise you will get Duct Height and Duct Width in different orientations and it will screw up when you try using duct sizing..
          Last edited by josephpeel; March 8, 2017, 03:30 PM.
          "One must imagine Sisyphus happy." Albert Camus - "The innovator has for enemies all those who have done well under the old conditions, and lukewarm defenders in those who may ​do well under the new." Nicolo Machiavelli -"Things that are too complex are not useful, Things that are useful are simple." Mikhail Kalashnikov

          Comment


            #6
            Many thanks, tzframpton and josephpeel.

            I will keep those in mind.

            Yes I am kind of having an AutoCAD MEP head on instead of an up and coming Revit head on, but one of my other problems is drawing a duct vertically, i.e., along the Z axis. Any duct that I draw, even from a point that is vertically orientated, is drawn on the XY plane! Grrrrr!

            Can anyone advise?

            Many thanks again, Tim.
            Tim Stretton ¦ AutoCAD MEP 2D & 3D & Autodesk Revit.
            (Used AutoCAD since release 12 & 13 in 1996. Learning Autodesk Revit, not BIM yet)
            “Eppur si Muove! (It [the Earth] still moves!)” —— Galileo Galilei (15-05-1564 › 08-01-1642)

            Comment


              #7
              Originally posted by Tim Stretton View Post
              Many thanks, tzframpton and josephpeel.

              I will keep those in mind.

              Yes I am kind of having an AutoCAD MEP head on instead of an up and coming Revit head on, but one of my other problems is drawing a duct vertically, i.e., along the Z axis. Any duct that I draw, even from a point that is vertically orientated, is drawn on the XY plane! Grrrrr!

              Can anyone advise?

              Many thanks again, Tim.
              I'm assuming you're in a 3D View. AutoCAD MEP has the Compass and it can "model" duct far better than Revit can. Way more intuitive in 3D space. When I'm in Revit I tend to stay in a Plan or Section View and bounce between them as needed. Revit doesn't do great at modeling systems in 3D View. It's definitely doable and it can achieve good results, but it's not at the caliber AutoCAD MEP is.

              -TZ
              Tannar Z. Frampton ™
              Frampton & Associates, Inc.

              Comment


                #8
                Originally posted by tzframpton View Post
                Revit doesn't do great at modeling systems in 3D View. It's definitely doable and it can achieve good results, but it's not at the caliber AutoCAD ..

                -TZ
                +2 Autocad 3D over Revit 3D every day of the week. It is the autodesk bimworld upside down.

                Comment


                  #9
                  Something to try in 3D is Set Workplane. If you use Rotate, it usually only rotates in the floor plane. Set the work plane (Pick a vertical face) and it will rotate that way instead. Drawing ducts vertically is restricted because they always work with an offset from the level. The best way to make vertical ducts is to draw horizontal ducts in a plan view while changing the offset, then delete the horizontal fittings if they are not needed. Or copy and rotate in Section/3D. (I dont use sections at all for working, they just clutter up your model and views. 'BX' to quickly generate a 3D view and check the coordination is much faster).

                  I really hope that adesk improve working in 3D, because with the focus on a 2D interface so much of the potential of Revit as a truly 3D environment to work in is lost. I guess they did it that way to help with the transition from acad for all the flat earthers.
                  "One must imagine Sisyphus happy." Albert Camus - "The innovator has for enemies all those who have done well under the old conditions, and lukewarm defenders in those who may ​do well under the new." Nicolo Machiavelli -"Things that are too complex are not useful, Things that are useful are simple." Mikhail Kalashnikov

                  Comment


                    #10
                    Sections are a must for me. Especially for working views. Gives you access to so much more information when coordinating a construction set via the BIM process with other trades. Even with working-view Sections, I still use BX a ton as well.

                    One argument for sections as a necessity would be leveling off an entire bank pipes on a trapeze hanger that are varying sizes. With many different sizes and OD's, it's impossible to get them all at the same BOP efficiently unless you're in a section, via align.

                    I can see the argument for no sections. But, just can't live without them at the moment. Definitely a part of my workflow.

                    -TZ
                    Tannar Z. Frampton ™
                    Frampton & Associates, Inc.

                    Comment

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