Research on Key Technologies of 3D Geological Model Rendering in Cloud Environment

3D model is a 3D digital representation of objective things, which has been widely applied in fields like urban construction, disaster prevention and mitigation, medical research, biological science, industrial manufacturing, agricultural production, etc. As a special 3D model, 3D geological model possesses the characteristics of 3D model and plays a fundamental role in geological survey, mineral exploitation, underground engineering and smart city construction.With the development of intelligent sensing technology and 3D geological modeling technology, the scale of 3D geological model data increases exponentially. Meanwhile, with the pace of large-scale underground engineering and smart city continuing to increase, 3D geological model with fine large scenes is being eagerly required. The rapid growth of data and the refinement of large application scenes bring new challenges to the real-time dynamic visualization of 3D geological models. These challenges are mainly reflected in the new technical problems related to 3D geological model rendering.This study focuses on 3D geological model rendering and puts forward the corresponding solutions. The validity of the technology has been proved by the simulation test of cluster cloud environment consisting of 5 computers. The technique has been applied in the construction of 3D geological information and visualization system in transparent Xiong’an.Firstly, the data organization mode of two common structures of 3D geological model (3D geological structure model and 3D geological high-precision grid model) is analyzed, and a distributed storage strategy of 3D geological model based on MongoDB is proposed. Aiming at the characteristics of multi-layer data in z-direction of 3D geological structure model, an octree index mechanism is proposed to improve the efficiency of data scheduling according to the z-direction spatial information and layer information. The rendering optimization of a single node 3D geological model is studied. The rendering in the cloud environment still needs the cooperation of each sub-node. Therefore, the overall rendering efficiency in the cloud environment can be improved by adopting efficient rendering optimization strategies for the 3D geological model of each node and selecting an effective node scheduling strategies. Single-node 3D geological model rendering is mainly performed by transferring data from memory to GPU. The communication between memory and GPU is a bottleneck, which will affect the overall rendering efficiency. Through the strategies of visibility elimination, LOD establishment, data merging and instance rendering optimization, this thesis effectively reduces the number of drawing calls and communication times. How to optimize and improve the overall performance of 3D geological model rendering in cloud environment from a global perspective is studied, and a multi-level distributed SCMP framework is proposed, which integrates the advantages of cluster, GPU, distributed storage, etc., to maximize the distributed computing ability of existing machines and improve the rendering efficiency in cloud environment. From the experimental data, the node invocation optimization strategy with “GPU+CPU” can ensure that the frame rate of the four rendering nodes and the end-user scene in the cloud environment is stable at about 35 frames per second, and can achieve satisfactory cluster load balancing effect.