Building complex roof modeling method and system

The embodiment of the invention provides a building complex roof modeling method and system, and the method comprises the steps: cutting a roof point cloud from an obtained house point cloud based on a determined eave height; based on a preset surface segmentation condition, performing surface segmentation on the roof point cloud to obtain a plurality of target roof planes; on the basis of each target roof plane obtained by segmentation, retaining a region surface of the plane in the roof bounding box to obtain an initial three-dimensional model; a linear programming problem of the three-dimensional model is defined, multiple types of binary variables are defined according to the topological structure of the linear programming problem, and the multiple types of binary variables comprise surface selection variables, edge selection variables and sharp edge selection variables; according to the attribute of the linear programming problem, defining a combination coefficient, and constructing a linear objective fu