slicing is one of the most fundamental geometric operations in Computer-Aided Design and Manufacturing (CAD/CAM). This paper presents a practical slicing algorithm that handles singular cases in a simple and robust ma...
详细信息
slicing is one of the most fundamental geometric operations in Computer-Aided Design and Manufacturing (CAD/CAM). This paper presents a practical slicing algorithm that handles singular cases in a simple and robust manner by making very small movements of vertices. The direction of the shifting is based on the manufacturing methodology of either material removal or deposition as well as singularity types. We evaluated our algorithm by implementing a slicer and applying it to various polyhedral models. The test results demonstrated that the proposed algorithm performed better than conventional slicing algorithms.
Additive manufacturing is capable of forming part solids from a digital model of the workpiece, which often needs to be sliced due to the nature of the process of stacking materials layer by layer. Previous algorithms...
详细信息
Additive manufacturing is capable of forming part solids from a digital model of the workpiece, which often needs to be sliced due to the nature of the process of stacking materials layer by layer. Previous algorithms require more time to order the intersection points during slicing and only consider a fixed axis vector as the slicing direction. With the increasing complexity of the workpiece model, it is necessary to improve the efficiency of the slicing algorithm, and the given slicing direction should be flexible and convenient. Therefore, this paper proposes an efficient algorithm for slicing in any direction using the shared edges of adjacent triangles. Firstly, the model can be efficiently sliced in any direction by custom vectors, which is convenient for process validation;secondly, the shared edges of neighboring triangular facets intersecting the plane need to be calculated only once to reduce redundant calculations;finally, the ordered intersections of the constructed inner and outer contours are directly outputted without any additional sorting to reduce the running time. The experimental results show that compared with other algorithms, the proposed algorithm can improve the execution efficiency and eliminate the constraint that the slicing direction is fixed on the Z-axis, which is of application value and reference significance for additive.
slicing is an important step for all layer-based additive manufacturing (AM) processes. This paper proposes an improved and robust slicing algorithm with efficient contour construction to reduce the slicing time and b...
详细信息
slicing is an important step for all layer-based additive manufacturing (AM) processes. This paper proposes an improved and robust slicing algorithm with efficient contour construction to reduce the slicing time and be able to slice a complex STereoLithography (STL) model with millions of triangles (resulting from high-accuracy STL files). Also, another important feature of the proposed method is it can identify outer and inner contours automatically. Test results to demonstrate the improvements in execution time and comparisons with results from published papers have been given to illustrate the algorithm efficiency. The robustness of this slicing algorithm is demonstrated by several complex models with large numbers of nested contours on each slice.
To date, slicing algorithms for additive manufacturing is the most effective for favourable triangular mesh topologies;worst-case models, where a large percentage of triangles intersect each slice plane, take signific...
详细信息
To date, slicing algorithms for additive manufacturing is the most effective for favourable triangular mesh topologies;worst-case models, where a large percentage of triangles intersect each slice plane, take significantly longer to slice than a like-for-like file. In larger files, this results in a significant slicing duration, when models are both worst cases and contain more than 100,000 triangles. The research presented here introduces a slicing algorithm which can slice worst-case large models effectively. A new algorithm is implemented utilising an efficient contour construction method, with further adaptations, which make the algorithm suitable for all model topologies. Edge matching, which is an advanced sorting method, decreases the number of sorts per edge from n total number of intersections to two, alongside additional micro-optimisations that deliver the enhanced efficient contour construction algorithm. The algorithm was able to slice a worst-case model of 2.5 million triangles in the 1025s. Maximum improvement was measured as 9400% over the standard efficient contour construction method. Improvements were also observed in all parts in excess of 1000 triangles. The slicing algorithm presented offers novel methods that address the failings of other algorithms described in literature to slice worst-case models effectively.
Although stereo lithography (STL) file format is widely used as a de facto industry standard in rapid prototyping (RP), there are in practice always some defects and shortcomings when the slicing output file (SOF) is ...
详细信息
Although stereo lithography (STL) file format is widely used as a de facto industry standard in rapid prototyping (RP), there are in practice always some defects and shortcomings when the slicing output file (SOF) is generated. As the model size and complexity grow, the defects grow exponentially and as a result it becomes impossible to fix the STL files manually. Modifying the head-to-tail algorithm, a new method that produces an error-free SOF (in spite of defects in the original STL file) with fewer data to analyse is presented herein. The nearest distance algorithm employed guarantees fully closed contours.
3D printing technology is a popular new technology that combines information technology with mechanical engineering and material science, and is being widely used in various fields. From the computer point of view, th...
详细信息
3D printing technology is a popular new technology that combines information technology with mechanical engineering and material science, and is being widely used in various fields. From the computer point of view, the basic technology of 3D printing is to slice and scan each part of the 3D model. The slicing algorithm used directly affects the speed of slicing and the effect of post-printing, and the result of slicing needs to be optimized. This paper analyzes the slicing algorithm and partition scanning strategy related technologies of 3D printing models and solves the practical problems of models in the 3D printing process. This paper first studies the slicing algorithm in the 3D printing process, then obtains and intercepts the cross-sectional contour, and finally performs mosaic and partition scanning on the sliced polygon, and uses experiments to verify the effectiveness of the research. The experimental results show that compared with other 3D printing methods, the printing method in this paper reduces the slicing time by 23.61%, and the fitting error range and the fluctuation range of the residual height of the fusion volume are smaller.
Constructing the topology of STL file efficiently is a key factor to improve the efficiency of slicing algorithm. In this paper a topology construction algorithm based on Standard Template Library set containers and a...
详细信息
ISBN:
(纸本)9780878492800
Constructing the topology of STL file efficiently is a key factor to improve the efficiency of slicing algorithm. In this paper a topology construction algorithm based on Standard Template Library set containers and a rapid slicing algorithm are developed. The algorithm developed removes a large number of redundant vertices, and only calculates intersection per triangular facet with slice plane once, and attains another point of intersection directly from the adjacent relations. In addition, the algorithm can reduce the times of traversing and sorting for the triangular facets, and also the times of calculation of intersection in the slicing processes, which results in the simplification of the process of constructing the slice contour, consequently the efficiency of the slicing algorithm is improved.
Three-dimensional (3D) point clouds are widely used for geomorphic change detection. However, the lack of efficient change-detection algorithms for complex terrain limits the use of 3D point clouds in area-wide morpho...
详细信息
Three-dimensional (3D) point clouds are widely used for geomorphic change detection. However, the lack of efficient change-detection algorithms for complex terrain limits the use of 3D point clouds in area-wide morphological change studies. In this study, a complex terrain development process was simulated on a natural slope in the hilly and gully Loess Plateau in China using 28 runoff scouring experiments conducted in two plots. Highly precise point clouds were obtained using terrestrial laser scanning (TLS) before and after each experiment. A slice contraction change detection (SCCD) algorithm was developed based on slicing, Laplacian-based contraction, and differential principles for detecting geomorphic and volumetric changes on complex terrain, and the level of detection (LoD) was derived with respect to that of the multiscale model to model the cloud comparison (M3C2) algorithm. The accuracy of SCCD was compared with that of the 3D-M3C2 algorithm (i.e., a 3D volumetric change calculation algorithm based on M3C2) and the digital elevation model (DEM) of difference (DoD) algorithm based on the measured sediment yield from the plots. The comparison was performed also under different point cloud densities and morphologies. Results showed the following: (1) The precisions of SCCD and 3D-M3C2 were comparable and considerably higher than that of DoD. The mean relative errors of SCCD, 3D-M3C2, and DoD for the two plots were 13.32% and 10.37%, 10.07% and 10.84%, and 35.30% and 27.23%, respectively. The relative error fluctuations of the three algorithms for the individual experiments followed the sequence of DoD (standard deviation (std.): 10.18) > 3D-M3C2 (std.: 8.29) > SCCD (std.: 5.79). (2) The sensitivity to point cloud density changes followed the sequence of 3D-M3C2 > SCCD > DoD as the point cloud density varied between 10,000 and 1000 points m- 2. The mean relative errors of 3D-M3C2, SCCD, and DoD for the two plots were 10.07-18.59% and 10.84-13.62%, 13.32-16.83
Three-dimensional display has been a widely researched technology, offering an abundance of depth cues to enhance the overall visual experience. The volumetric display system has significant advantages due to its abil...
详细信息
Three-dimensional display has been a widely researched technology, offering an abundance of depth cues to enhance the overall visual experience. The volumetric display system has significant advantages due to its ability to be viewed from any angle and without the need for auxiliary devices. However, the issue of deviation between the rotating axis and the display plane was not taken into consideration in the previous systems. Therefore, we innovatively propose an axis-shift slicing algorithm for volumetric display systems, leading to improved accuracy and reliability of the image slices data. Moreover, a prototype based on a novel collaborative control scheme as well as a creative software simulator is designed and implemented, laying the foundation for further development and refinement. Finally, the results from both simulations and experiments have demonstrated the effectiveness of the proposed axis-shift algorithm and the designed volumetric display system.
To overcome the inefficiency of slicing process of rapid prototyping based on STL models, an improved slicing algorithm is proposed. The method builds integral topology of STL models in advance using a Hash table, whi...
详细信息
To overcome the inefficiency of slicing process of rapid prototyping based on STL models, an improved slicing algorithm is proposed. The method builds integral topology of STL models in advance using a Hash table, which enables to get contours directly, and then reduces the search range in slicing by establishing the slicing relation matrix, which can effectively reduce the time cost of slicing. It has been demonstrated that the algorithm has nearly linear time complexity. The method is proved to be effective and efficient through application cases, and the results show better performance than other existing algorithms, especially when the STL model is complex or large.
暂无评论