Forward And Reverse Modeling Of Ancient Architecture Timber Structure Based On Point Cloud And Parameter Model

The wooden structure of ancient Chinese architecture contains profound cultural details and the wisdom of the working people.However,with the passage of time,natural disasters and economic development,existing ancient architecture have suffered from varying degrees of damage or even destruction,and effective measures have been taken.In the past,archiving methods of ancient architecture data were photos,texts,tables,etc.The information capacity was small and difficult to preserve.The application of digital technology of ancient architecture and the establishment of three-dimensional models provided a new idea for data archiving of ancient architecture.The commonly used methods used to model the structural components of ancient architectural wood structures are which inverse modeling of using point cloud dataand forward modeling using size parameters.However,due to the characteristics of lasers and the characteristics of ancient architecture structures,occlusion can cause vulnerabilities.While using the dimensional parameters for forward modeling,although a complete model can be obtained,the reality of the surface of wooden structural components of ancient architecture is lacking.Both methods can be used to obtain ancient architecture.However,as the basic data for the protection,repair,reconstruction,and monitoring of ancient architecture,wooden structural components need to be complete and realistic.The researchs fail to achieve its purpose.In order to obtain a complete and realistic ancient architecture components models,based on the analysis of the structural characteristics,this paper analyzes and compares two modeling methods that use dimensional parameters for forward modeling and inverse modeling using three-dimensional laser point cloud data.This paper propose a forward and reverse modeling method,the main contents and results are as follows:1.Basic research on the structural characteristics and forward and reverse modeling methods of wood structures in ancient architecture.Through the reading of ancient books,the structural characteristics of the components are summarized,organized into tables which searve as the data reference for forward modeling,and the analysis applied to ancient architecture components.Using two modeling methods to establish models,and analysis the advantages and disadvantages of two modeling methods.2.Perform the registration of the forward and reverse models of the ancient architecture structure.After the format of the model data obtained by the two modeling methods is unified,the geometric location features of the ancient architecture are obtained by using the slicing technology of the model data.Using the least-squares fitting of the coordinates of the circle and the polygon and the center axis.Using initial geometry of ancient architecture for initial registration,and using ICP algorithm of accurate registration.Good accuracy provides the guarantee for the subsequent grid deformation technology.3.A forward and inverse modeling method based on Laplacian coordinate deformation is proposed to construct a complete and realistic component model of ancient architecture wood structure.First,apply the inverse model of laser scanning point cloud data to get the real component model,and use the standard size parameters obtained from ancient books to get the standard component model.Secondly,after the models are registered,taking the realistic component model as the target model,the paper use contour points as the deformed constraint points to deform the standard component model to obtain a complete and realistic component model.4.Analysis of deformation of wooden structures components in ancient architecture.By comparing the deformed standard component model with the original standard component model,the deformation of wooden structural components in ancient architecture was analyzed,in which the normal deviations were used to quantify the surface deformation of the ancient architecture,the offset of the column was indicated by the offset of the column head.These data can be used to predict and analyze the safety of ancient architecture structures.5.Some component models of Zhonghe Dian were used as experimental data,the experimental results show that the technology roadmap is feasible,the deformation model has good performance details,and a complete and realistic model of ancient architecture components can be obtained.Simultaneously,using OpenGL,Qt Designed to achieve 3D visualization system to display results and verify the feasibility of the technical route.Using this technology route to obtain a complete and realistic component model has the advantages of small data volume,easy storage,and the advantages of lightweight browsing.A complete and realistic wood structural components model not only digitally protects in a threedimensional format,but also provides basic data for subsequent structural monitoring and health monitoring.The component model has practical significance for the protection of ancient architecture in the application of protection,academic research,and social services.