How to add the opening cut in order to pierce the wall when creating a new family of walls from Grasshopper with Rhino inside components?
You can not create a family of “Walls” in Revit. Walls are system families. But you can create wall-like geometry and place them inside a Revit family. If you are creating wall-like geometry, you are not limited to the Revit components and can process and carve the geometry as you wish using the standard GH components, before pushing them to Revit.