Abstract: Floor slab cutting is fundamentally a polygon clipping problem. However, existing algorithms involve complex data structures and implementation processes, making them difficult to apply broadly in practice. While some mainstream BIM software on the market offer floor slab cutting functions, most can only handle regular slabs and cannot address complex boundaries such as curves and concave polygons. This paper presents two new methods for cutting floor slabs in Revit. The first method is based on geometric calculations, which solves the new profile after cutting by sorting collision points between the cutting lines and the original slab contour lines. This method is applicable to BIM software platforms beyond Revit and has a broad range of applicability. The second method, based on the concept of dimensional elevation, transforms the two-dimensional problem into a three-dimensional one and utilizes Revit's open 3D solid Boolean operation interface for solving. Both methods avoid complex data structures and are easy to implement, providing valuable references for developers involved in secondary development.