查看更多>>摘要：In computer graphics, non-photorealistic rendering (NPR) is an important branch. NPR technology is to achieve a variety of artistic effects through the computer, such as oil painting, cartoon, watercolor and other effects. The purpose of this paper is to automatically convert the 3D model into two-dimensional Chinese ink painting effect on graphics processing unit (GPU), and has improved the traditional algorithm that has some lacks of rendering effect. The algorithm is divided into two major steps: contour line rendering, and interior rendering. For contour line rendering, on the basis of the traditional extraction of contours, this paper adds self-bold, particle diffusion and other steps. For interior rendering, on the basis of the traditional layered rendering of diffuse lighting, two methods are added. The first method is based on the mean filtering, and the filter kernel is stratified by the principle of percentage-closer soft shadows (PCSS). The second method is Noise texture mapping, to obtain an ink diffusion effect.
查看更多>>摘要：Superpixel segmentation is the oversegmentation of an image into a set of homogeneous regions. Superpixel has many specific properties and has been commonly used as supporting regions for primitives to reduce computations in various computer vision tasks. One property of superpixels is compactness, which is preferred in some applications. In this paper, we give an review on image superpixel segmentation algorithms proposed in recent years. Superpixel segmentation approaches are classified based on the compactness constraint and their main idea are introduced. We also compare these algorithms in visual and evaluate them with five common measurements.
查看更多>>摘要：This paper constructs a tree model by using the 3D stochastic and L system with brackets. Adjusting the range of the parameters, the present method ensures a favorable randomness and reflects the reality and the real time. Based on a simple mechanical model, the simulation of the phenomenon of wind swaying trees satisfies visual effects well.
查看更多>>摘要：We present the solid model edit distance (SMED), a powerful and flexible paradigm for exploiting shape similarities amongst CAD models. It is designed to measure the magnitude of distortions between two CAD models in boundary representation (B-rep). We give the formal definition by analogy with graph edit distance, one of the most popular graph matching methods. To avoid the expensive computational cost potentially caused by exact computation, an approximate procedure based on the alignment of local structure sets is provided in addition. In order to verify the flexibility, we make intensive investigations on three typical applications in manufacturing industry, and describe how our method can be adapted to meet the various requirements. Furthermore, a multilevel method is proposed to make further improvements of the presented algorithm on both effectiveness and efficiency, in which the models are hierarchically segmented into the configurations of features. Experiment results show that SMED serves as a reasonable measurement of shape similarity for CAD models, and the proposed approach provides remarkable performance on a real-world CAD model database.
查看更多>>摘要：In 3D models retrieval, feature description and retrieval of non-rigid model face more complex problems due to the isometry transformation of itself. We introduce the hierarchical combination matching into the feature comparison, and build a map between the divided regions of two models, and then achieve accurate feature matching based on patch-by-patch, which successfully introduces the spatial information into feature matching. Verified by experiment, the 3D model retrieval method proposed in this paper based on hierarchical combination matching can make sure more accurate feature matching, so as to enhance the precision of retrieval.
查看更多>>摘要：It is proved that among the regular polygons with prime edges, only the regular polygons with Fermat prime edges are constructable with compass and straightedge. As 17 is a Fermat prime number, the construction of heptadecagon has been discussing all the time. Many different construction methods are proposed although they are based on the same theory. Simplification of the construction is still a sensible problem. Here, we propose a simple method for constructing regular heptadecagon with the fewest steps. The accumulation of construction errors is also avoided. This method is more applicable than the previous construction.
查看更多>>摘要：The electromagnetic balance head is used for balancing the electric spindle. This paper analyzes the internal structure of the electromagnetic balance head and introduces the structure of the counterweight plate and the range of the balance in the moving ring .The principle of how the electromagnetic field generated by the static coil acts on the moving ring is also investigated. The model is built in Ansoft Maxwell and the excitation parameters and boundary conditions are set up. Through the analysis of the magnetic field generated by the static coil in the position of the moving ring, it is verified that the static loop coil can drive the counterweight plate.
查看更多>>摘要：This paper introduces the PKPM-BIM construction management platform and its applications in the construction security management. The PKPM-BIM platform is an integrated management system mainly developed for the contractors to implement the BIM-aided construction management. Application of BIM technology would bring many beneficial changes to the security management in construction.
查看更多>>摘要：This paper mainly discusses the problems existing in the traditional design process of the refrigeration station and tries to solve them with BIM technology. Considering the characteristics of BIM technology, BIM design process is presented based on the traditional design process to achieve the goal of improving design quality and efficiency.
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