Revit 2016/2017 has the ability to both read and write Fabrication .MAJ files. This means we have a bidirectional work flow between the Fabrication software CADmep and Estmep and Revit.
Historically this has not been possible as .dwg files created in CADmep have required an object enabler to show the OLE objects i.e. the Pipe, Ductwork and containment systems. Although you could use this enabler in Navisworks one was not available for Revit.
The only way to show this in Revit would have been using say an IFC or .dwg that had been converted to a basic file. This on its own meant the data could not be edited or changed.
The key to this functionality is through the use of the Fabrication Extension for Revit, you can find this for free on the Autodesk Exchange Apps, Search Fabrication.
This will allow you to Import any .maj file using the same database used in Autodesk Architecture, Engineering & Construction Collection. It will also allow you to modify it using the new fabrication parts tool.
Alternatively, you can now in Revit 2017 convert Revit duct and pipe to fabrication parts and export them using the Design to Fabrication (Currently this functionality is not available for containment). This is quite a cool feature as it now means it is possible to both design using the fluid workflows in Revit but also take into consideration fabrication workflows.
Revit has always had an issue with insertion lengths so if you are using Revit to calculate the total length of pipe work needed in a job it would not take into account the insertion of the pipe into a fitting, this has normally been done by adding a calculation to the schedules.
The process for converting the Revit systems is quite straight forward and can be done even if you do not have access to the fabrication software. Revit comes with a basic library of fabrication parts, 2017 even more so.
Start by selecting the system you wish to convert and click the Design to Fabrication tool, if you have not done so already you will be asked to choose the configuration you wish to use, in this case HVAC General Supply from the metric content library.
Notice although it has created the system using fabrication parts it has not yet broken down the duct in to fabrication lengths.
We still have one more step to go, this is to select the duct lengths and use the optimize lengths tool from the modify tool bar.
We can now create a new .maj from the resulting fabrication parts to use in any of the fabrication products, including CAMduct to send the design straight to the shop floor manufacturing equipment.