By default, all Parts and Assemblies within the 3D Scene should have "Include in BOM" selected (within the Properties Browser), as you normally want these to be included in a BOM. However, there are some exceptions, such as Construction Items (like Layout Sketches) and Reference Parts (like existing Parts or a Building etc...). For these items you would deselect "Include in BOM" when you create them. However, if the Referenced Parts have other 2D drawings referencing them (which might be the cas