{"topic":{"id":13932,"title":"实验 2.9 Loop 曲面细分和实验 2.8 基于半边的局部操作","slug":"topic","userId":1202,"categoryId":56,"createdAt":"2024-11-30 08:58:02.612173","bumpedAt":"2024-12-02 14:41:37.084264","views":297,"postsCount":2,"highestPostNumber":2,"likeCount":0,"closed":false,"pinned":false,"pinnedGlobally":false,"pinnedAt":null,"pinnedUntil":null,"isBanner":false,"excerpt":"Loop 曲面细分中如果要正确处理不封闭的 mesh，是不是需要在实验 2.8 中正确实现对边界边的边分裂操作？还有对边界边作分裂时，我始终得不到正确的结果，是不是我对属于一个“虚假的”面的半边的处理不对，文档中没太说清楚 prev、next 等是怎么做的？我仔细检查各个量的邻接关系没有找到错误。","deletedAt":null,"isAnonymous":false,"isPrivate":false,"isMembersOnly":false,"category":{"id":56,"name":"计算机图形学","slug":"cg","color":"92278F"},"author":{"id":1202,"username":"shinnrryuu","name":"神竜","avatarUrl":"/uploads/image/bc/31/bc31850c60444497d7b0f17ffcdc4665bc4f1cdebdce58efd973839de6349398.avif"},"realAuthor":{"id":1202,"username":"shinnrryuu","name":"神竜","avatarUrl":"/uploads/image/bc/31/bc31850c60444497d7b0f17ffcdc4665bc4f1cdebdce58efd973839de6349398.avif"},"tags":[]},"posts":[{"id":43794,"postNumber":1,"raw":"Loop 曲面细分中如果要正确处理不封闭的 mesh，是不是需要在实验 2.8 中正确实现对边界边的边分裂操作？\n还有对边界边作分裂时，我始终得不到正确的结果，是不是我对属于一个“虚假的”面的半边的处理不对，文档中没太说清楚 prev、next 等是怎么做的？我仔细检查各个量的邻接关系没有找到错误。\n[grid mode=\"tile\"]\n![image|585x500](/uploads/image/0a/65/0a65ea12d7262099d54b62e84a2b1647d6730dcef9d2863fcdf2d51589ed4ab4.avif)\n![image|681x500](/uploads/image/56/53/5653426724f42d2f15ed26c8ec57908f46db47154ab9a7993d7eaa2785ae9dc5.avif)\n![image|690x433](/uploads/image/d2/d4/d2d4b36f0dea6249fdc3c9392872207ee58868789bf53cd912f48cacfe3d7c57.avif)\n[/grid]","cooked":"

Loop 曲面细分中如果要正确处理不封闭的 mesh，是不是需要在实验 2.8 中正确实现对边界边的边分裂操作？
\n还有对边界边作分裂时，我始终得不到正确的结果，是不是我对属于一个“虚假的”面的半边的处理不对，文档中没太说清楚 prev、next 等是怎么做的？我仔细检查各个量的邻接关系没有找到错误。

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\n","createdAt":"2024-11-30 08:58:02.844122","updatedAt":"2024-11-30 08:58:02.844122","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":132,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":1,"publicVersion":1,"deletedAt":null,"foldedAt":null,"isAnonymous":false,"isOwner":false,"user":{"id":1202,"username":"shinnrryuu","name":"神竜","avatarUrl":"/uploads/image/bc/31/bc31850c60444497d7b0f17ffcdc4665bc4f1cdebdce58efd973839de6349398.avif","admin":false,"moderator":false,"signatureRaw":null,"signatureCooked":null}},{"id":43894,"postNumber":2,"raw":"看文档我觉得需要格外注意 __一条边界 (a boundary)__ 和 __一条边界边 (a boundary edge)__ 概念的区别，dandelion 中，一条边界上的所有边共享一个 virtual face \n\n举个例子就是，一个立方体上有一个洞，洞口由 20 条 boundary edge 构成，那么这个洞对应一个 virtual face，而这 20 条边靠近洞一侧的 20 条半边首尾相连成环，都隶属于那一个 virtual face。\n\n这也说明，一个 boundary halfedge 的 prev 和 next 是相邻的 boundary halfedge。\n\n你的代码中，boundary halfedge 的 next 和 prev 都成了自身了，这肯定是错的。建议使用 validate() 函数，检查自己操作完还符不符合半边网络数据结构。","cooked":"

看文档我觉得需要格外注意 一条边界 (a boundary) 和 一条边界边 (a boundary edge) 概念的区别，dandelion 中，一条边界上的所有边共享一个 virtual face

举个例子就是，一个立方体上有一个洞，洞口由 20 条 boundary edge 构成，那么这个洞对应一个 virtual face，而这 20 条边靠近洞一侧的 20 条半边首尾相连成环，都隶属于那一个 virtual face。

这也说明，一个 boundary halfedge 的 prev 和 next 是相邻的 boundary halfedge。

你的代码中，boundary halfedge 的 next 和 prev 都成了自身了，这肯定是错的。建议使用 validate() 函数，检查自己操作完还符不符合半边网络数据结构。

\n","createdAt":"2024-12-02 14:41:37.084264","updatedAt":"2024-12-02 14:45:17.690487","replyToPostNumber":null,"replyCount":0,"likeCount":0,"wordCount":195,"liked":false,"bookmarked":false,"polls":[],"reactions":[],"wiki":false,"version":1,"publicVersion":1,"deletedAt":null,"foldedAt":null,"isAnonymous":false,"isOwner":false,"user":{"id":3740,"username":"Lskyi","name":null,"avatarUrl":null,"admin":false,"moderator":false,"signatureRaw":null,"signatureCooked":null}}],"hasMore":false,"lastReadPostNumber":1,"hasUrlPostNumber":false}