Quantitative Comparison of Lidar Data and User-generated Three-dimensional Building Models From Google Building Maker

Volunteered geographic information (VGI) has received increased attention as a new paradigm for geographic information production, while light detection and ranging (LiDAR) data is widely applied to many fields. This study quantitatively compares LiDAR data and user-generated 3D building models created using Google Building Maker, and investigate the potential applications of the quantitative measures in support of rapid disaster damage assessment. User-generated 3D building models from Google Building Maker are compared with LiDAR-derived building models using 3D shape signatures. Eighteen 3D building models are created in Fremont, California using the Google Building Maker, and six shape functions (distance, angle, area, volume, slope, and aspect) are applied to the 18 LiDAR-derived building models and user-generated ones. A special case regarding the comparison between LiDAR data and building models with indented walls is also discussed. Based on the results, several conclusions are drawn, and limitations that require further study are also discussed

Modeling of solids for three-dimensional finite element analysis

Journal ArticleThe geometric modeling of solid objects is a major problem within the design analysis loop of the engineering design process. Models are analyzed by various computer programs to predict their performance. The format of each model is usually different for each analysis routine. The existence of several versions of model, each of which may be independently modified, results in severe inconsistencies. The solution to this problem is to model the object at a higher level of abstraction. All other models are derived from the one high level model and all modifications are made to this model. The proposed form of the high level model is an extension of the parametric representation used for work with curves and surfaces. Representations of bivariate forms are extended to schemes for trivariate forms. The analysis of interest to this work has been the finite element method. The formulation of the finite element method was investigated to provide a geometric criterion for evaluation of the model for analysis. A new technique has been developed for deriving improved analysis models from the trivariate representation. Computer programs have been implemented to demonstrate these ideas and four examples are included