3D MODELLING WITH REUSABLE AND INTEGRATED BUILDING BLOCKS Sabry El-Hakim 1 , Emily Whiting 2 , Lorenzo Gonzo 3 1 VIT, National Research Council of Canada 2 Dept. of Architecture, MIT, USA 3 ITC-irst, Trento, Italy Email: sabry.el-hakim@nrc-cnrc.gc.ca Abstract: The creation of highly detailed components presented in this paper builds upon our previously introduced technique for creating complete models from only a small number of measured seed points. Here, we aim at increasing the level of automation in 3D reconstruction of scenes from a small number of images. We build highly detailed model components, for example; windows, columns, groin-vaulted ceilings elements, and arches with large number of automatically created points. The components are created to be reusable in other parts of the model, or any other model, which are similar in shape, but may vary in dimensions. Our approach works directly on the images and performs accurate transformations and scaling automatically without trials and errors. We developed a copy and paste procedure that automatically re-triangulates the base model to account for the pasted element. By creating reusable higher-level building blocks that can be integrated to form a highly detailed model, a growing library of image-based reusable components will materialize. This will significantly reduce the effort, time, and expertise required to create detailed 3D models from images. 1. Introduction Although 3D modelling from images has advanced significantly over the past decade, it is still difficult to learn and time consuming to create accurate, detailed, and realistic models of complex sites and structures. In this paper, we continue the efforts of increasing the level of automation of image-based modelling techniques. Previously [4], we have developed a semi- automated technique to build models of basic shapes using only a small number of interactively measured seed points. Here, we extend this technique to automatically add large numbers of 3D points and build model components, for example; windows, columns, groin- vaulted ceilings elements, and arches, to be reusable with other parts of the model or any other model similar in shape, but may vary in dimensions. Although similar facilities are available in commercial CAD and modelling software (like the clone command in 3dsmax) and some CAD modelling techniques [6, 9], we extended this idea to work directly on the images and perform accurate transformations and scaling without trials and errors. The drawback of CAD techniques, or ant technique that uses details from a computer-generated library of objects, is that those retrieved details are usually not the exact shape as the actual detail. This usually results in manual modification and many trials until the results are satisfactory. In an image- based approach, if no exact shape match is found in the library, the item can be modelled from 7th Conference on Optical 3-D Measurement Techniques. Oct. 3-5, 2005. Vienna, Austria.