Unity-based three-dimensional model lightweight method

The invention relates to a lightweight method, in particular to a Unity three-dimensional model-based lightweight method, belongs to the technical field of BIM (Building Information Modeling) digital design, and specifically needs the processes of digital-analog separation, model lightweight and rendering, data cleaning and arrangement, software secondary development and uploading to an intelligent power plant digital engineering platform. A model scene reconstruction mode is adopted in the model lightweight and rendering process, and the model scene reconstruction mode comprises the steps that firstly, a BIM model is analyzed and simplified, the name category of the original BIM model is allocated to a processing sub-process to be processed, scene reconstruction is conducted on the BIM model after processing is completed, and a strategy is made to conduct geometric figure simplification on the BIM model; decomposing the engineering related content into a plurality of dimensions and a plurality of layers by a