The light environment created by natural light is preferred by public due to its own economic, natural, pleasant and irreplaceable characteristics. Natural lighting is not only conducive to energy conservation of lighting, but also conducive to increasing the exchange of natural information indoor and outdoor, improving the space health environment and regulating the mood of space users. Making full use of the natural light in the building is of great significance for creating a good light environment, saving energy, protecting the environment and building green buildings. Therefore, it is necessary to optimize the lighting design of buildings. This paper puts forward an idea of natural lighting analysis in building based on the BIM technology and the BP neural network. Taking the CDUT library (library of Chengdu University of Technology) as an example, a 3D visualization model is established by using Revit software to generate the building information file in gbXML format. Then, the gbXML file is imported into Ecotect software to simulate and analyze the indoor light environment of the library, to calculate the natural lighting coefficient, and to quantitatively analyze the impact of window height, glass transmittance and wall material light reflectivity on the indoor light environment. At last, with the help of Weka software, the neural network model based on BP algorithm is established, obtaining the BP neural network model which can predict the variation range of variables under the optimal lighting coefficient.

As an indispensable work in the construction process, the foundation pit deformation monitoring plays a very important role in improving the quality and safety of the whole building. Therefore, after the completion of foundation pit construction, a combined foundation pit deformation monitoring method of the traditional one and the 3D laser scanning technology is conducted for monitoring the foundation pit deformation, making the monitoring more intuitive, which promotes the overall quality of the foundation pit. This paper mainly introduces the basic principles of 3D laser scanner, as well as its advantages over traditional surveying and mapping methods. Taking the foundation pit of the new student service center in dalian university project as an example, this paper also describes the method and process of using 3D laser scanning technology to model the foundation pit surveying and mapping, and also summarizes and prospects the application of 3D laser scanning technology in the foundation pit construction.