Octree-to-BRep conversion for volumetric NC simulation
Octree-to-BRep conversion for volumetric NC simulation
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DOI：
10.1007/s00170-005-0310-8
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发表时间：
2007-02
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影响因子：
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通讯作者：
K. Karunakaran;R. Shringi
中科院分区：
文献类型：
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作者：
K. Karunakaran;R. Shringi
用户友好性（如易于创建和修改）和系统友好性（如空间和时间复杂性、准确性等）是选择实体表示方案的两个重要标准。没有一种单一的实体表示方案能够完全满足用户友好性和系统友好性的所有要求。因此，任何实际的CAD/CAM系统都同时以多于一个的实体表示方案来维护对象的几何形状。因此，通常需要将一种实体表示方案转换为另一种实体表示方案。作者开发了一个体积数控仿真系统，其中瞬时毛坯表示为八叉树，因为它的空间和时间复杂性与NC块的数量无关。然而，由于八叉树本身不容易用于诸如任意变换、渲染显示等操作，它不能直接用于动画显示、验证和优化等下游应用，而边界表示则适用于这些下游应用。因此，需要将瞬时坯料的八叉树转换为BRep。本文提出了一种有效的算法，这种转换。该算法基本上将八叉树分成三个四叉树，它们沿着三个主方向存储几何图形。该算法是快速的，因为它只涉及树遍历。
User-friendlinesssuch as ease of creation and modification andsystem-friendlinesssuch as space and time complexities, accuracy etc. are two important criteria for the selection of a solid representation scheme. No single solid representation scheme fully meets all the requirements of user-friendliness and system-friendliness. Hence, any practical CAD/CAM system maintains the geometry of the objects in more than one solid representation scheme simultaneously. Therefore, it is often required to convert one solid representation scheme to the other. The authors have developed a volumetric NC simulation system in which the instantaneous blank is represented as an octree as its space and time complexities are independent of the number of NC blocks. However, since octree does not lend itself readily for operations such as arbitrary transformations, rendered display etc., it is not directly usable for downstream applications such as animated display, verification and optimization.Boundary representationis suitable for these downstream applications. Therefore, it is required to convert octree of the instantaneous blank into BRep. An efficient algorithm for this conversion is presented in this paper. This algorithm essentially splits the octree into three quadtrees that store the geometry along the three principal directions. This algorithm is fast as it involves only tree-traversals.