Unfortunately you can’t simply link in a 3d DWG to your project and cut sections through the linked 3d DWG data.
To get a true section through a 3d DWG in Revit, you must approach it in one of three ways.
- Within your project create an inplace family, making sure that you select an appropriate family category which allows the geometry to be cuttable. Then import the 3d DWG into the inplace family. This is no preferable, as you are adding weight to your project.
- Create a new family component such as a generic model family, which allows your geometry to be cuttable. Import the 3d DWG into the family then load this into your project and place the family. This approach allows you to manage the data a little easier as you can easily delete the family component from your project when it’s no longer required.
- If you have a very large 3d DWG survey that you want to use within your project you may be better using the above approach of creating a family component and then placing the component into a new project. Then link this “survey” project into you master project file. This keeps the 3d DWG survey data separate from the building model and makes the update process and management of the data a lot easier.