Importing Structural Elements from AutoCAD Architecture and AutoCAD MEP

Importing AutoCAD Architecture and AutoCAD MEP Layers

In AutoCAD Architecture and AutoCAD MEP, object components are placed on layers. A wall, for example, can be placed on layer A-Wall-G, whereas a door in the wall would be placed on layer A-Door-G. Layers can be created according to architectural standards like the AIA layer standard, or they can be user-defined. When an AutoCAD Architecture or AutoCAD MEP drawing is imported into Revit, the layer information of the imported objects is retained. Revit does not use layers internally, but it can map layers to object categories. When an imported drawing is exported back to AutoCAD Architecture or AutoCAD MEP, the layer settings of exported objects are exported with the objects. Revit objects that were added get a layer assigned based on the mapping of the object categories to layers in the layer mapping file. For example, if objects of the category Railing Balusters have been assigned to the layer A-FLOR-HRAL, they will appear on that layer when exported to AutoCAD Architecture or AutoCAD MEP. For more information, see Exporting to CAD Formats.

When AutoCAD Architecture or AutoCAD MEP drawings are imported into Revit, you can import all layers, or select individual layers to import. For example, if you are importing a floor plan and want only the structural members to display, you can select only the layers S-Column-G, S-Brace-G, and S-Beam-G. Only those layers will be imported, and as a consequence you will not see any walls, doors, or annotation objects in Revit. For detailed information, see Import and Link Options.

Exploding Imported Objects

When you import an AutoCAD Architecture or AutoCAD MEP drawing into Revit, the complete drawing is imported or linked as an Import Symbol. You can work more efficiently with the imported data by performing a partial explode on the imported drawing. This is the only way in which you can access the AutoCAD Architecture or AutoCAD MEP properties of individual objects. A partial explode breaks up the imported drawing into individual object blocks, but not into Revit lines and text elements. For more information, see Explode Imported Geometry.

You can explode or partially explode an imported drawing only using the Import tool in Revit. You can never explode or partially explode a linked drawing.

Removing Imported Objects from Revit

After you have imported structural members from AutoCAD Architecture or AutoCAD MEP and created corresponding Revit objects from them, you can keep the imported objects in the drawing or remove them in one of the following ways, depending on your requirements:

• Delete. If you have no further use for the imported objects, you can delete them from the Revit file.
• Unload. If you have linked to the AutoCAD Architecture or AutoCAD MEP drawing instead of importing it, you can unload the link in Revit. The drawing will no longer appear, but it can always be reloaded if needed, giving you the most up-to-date version. (If you want the objects to be frozen, you should import the drawing rather than link to it.)
• Delete individual layers. When an AutoCAD Architecture or AutoCAD MEP drawing is imported into Revit, the information about its drawing layers persists. As a result, you can selectively delete individual layers and the objects contained on them.