{"id":4651,"date":"2021-06-05T17:42:16","date_gmt":"2021-06-05T16:42:16","guid":{"rendered":"https:\/\/www.katsbits.com\/codex\/?p=4651"},"modified":"2023-09-07T15:50:55","modified_gmt":"2023-09-07T14:50:55","slug":"merge-at-intersection","status":"publish","type":"post","link":"https:\/\/www.katsbits.com\/codex\/merge-at-intersection\/","title":{"rendered":"Merge Edges at Intersection"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_83 counter-hierarchy ez-toc-counter ez-toc-light-blue ez-toc-container-direction\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-6a15d92069647\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-6a15d92069647\"  aria-label=\"Toggle\" \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.katsbits.com\/codex\/merge-at-intersection\/#merge-vs-merge\" >Merge vs Merge<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.katsbits.com\/codex\/merge-at-intersection\/#auto-merge\" >Auto Merge<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.katsbits.com\/codex\/merge-at-intersection\/#moveedit-edge\" >Move\/Edit Edge<\/a><\/li><\/ul><\/nav><\/div>\n<p>Overview of merging edges at an intersection.<br \/>\n<video poster=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/merge-at-intersection_mp4.jpg\" controls=\"controls\" width=\"100%\" height=\"auto\"><source src=\"https:\/\/www.katsbits.com\/media\/merge edges at intersection.mp4\" type=\"video\/mp4\" \/><!--<source src=\"https:\/\/www.katsbits.com\/images\/tutorials\/collections\/collection-shortcut.ogg\" type=\"video\/ogg\" \/>\n<source src=\"https:\/\/www.katsbits.com\/images\/tutorials\/collections\/collection-shortcut.webm\" type=\"video\/webm\" \/>--><\/video><\/p>\n<p>When editing meshes there is often a need to merge or join edges or other elements together where they intersect, cross or meet to form new structures. Typically this could be done using a <a href=\"https:\/\/www.katsbits.com\/codex\/boolean\/\">Boolean<\/a> operation on two or more objects, or more simply using the <b>Auto Merge<\/b> feature\/function.<\/p>\n<blockquote style=\"background-color: #ddecf3; color: #000;\"><p><b>Download<\/b>: <a href=\"https:\/\/www.katsbits.com\/files\/blender\/katsbits - intersection merge.zip\">merge at intersection<\/a> example file (c. 200 kb).<\/p><\/blockquote>\n<h3><span class=\"ez-toc-section\" id=\"merge-vs-merge\"><\/span>Merge vs Merge<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>In this context <a href=\"https:\/\/www.katsbits.com\/codex\/?s=merge\">merging<\/a> creates a new sub-element where two or more edges cross [1] rather than removing or cleaning up a structure as would ordinarily be done using <a href=\"https:\/\/www.katsbits.com\/codex\/merge\/\">Merge<\/a>. In other words, where the intersection occurs Blender places a new vertex that acts as a structural element from which all connected edges then flow.<\/p>\n<blockquote><p><b>Design note<\/b>: once the vertex is placed there is typically no need to <a href=\"https:\/\/www.katsbits.com\/codex\/remove-doubles\/\">Clean Up<\/a> the mesh unless newly created vertices are not coincidental (occupy the same coordinates in space).<\/p><\/blockquote>\n<p><a href=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/intersection-merge.jpg\" target=\"_blank\" rel=\"noopener\"><img decoding=\"async\" style=\"width: 100%; height: auto;\" src=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/intersection-merge.jpg\" alt=\"Merging sub-objects at Intersection\" width=\"900px\" height=\"500px\" border=\"0\" \/><\/a><br \/>\n<i>Two sub-meshes that need to be merged or joined where edges intersect each other [1] &#8211; as they are part of the same Object it&#8217;s not possible to use Boolean or similar operations in this context.<\/i><\/p>\n<h3><span class=\"ez-toc-section\" id=\"auto-merge\"><\/span>Auto Merge<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><b>Step 1<\/b>: To merge at an intersection open the <b>Sidebar<\/b> if not already visible &#8211; <i>View \u00bb Sidebar or press <span class=\"shortcutkey\">N<\/span><\/i>) &#8211; and access the <b>Tool<\/b> panel [2]. Here expand <b>Options<\/b> (click the down-arrow) and enable <b>Auto Merge<\/b> [3] to activate the main feature, then optionally <b>Split Edges &#038; Faces<\/b> [4] &#8211; this is the active function that splits elements where they intersect, creating the new sub-elements as necessary. Once the core settings are active, depending on the complexity of the merge required, the number of intersecting edges there may be, <b>Threshold<\/b> can be set to change the likelihood new vertices are merged together (in-situ <a href=\"https:\/\/www.katsbits.com\/codex\/remove-doubles\/\">Clean Up<\/a> or &#8216;rem dub&#8217;).<\/p>\n<blockquote><p><b>Design note<\/b>: although merging uses vertices to control mesh structure, the operation itself can be initiated in Vertex, Edge or Face selection, behaving appropriately based on the active mode (see &#8216;Face Select&#8217; boxout below).<\/p>\n<p>The options to merge can also be found in the <b>Tool Settings<\/b> header running along the top of the 3D Viewport. If not visible, from the <b>View<\/b> menu select <b>Tool Settings<\/b> (checkbox) &#8211; <b>View \u00bb Tool Settings<\/b>. To the right of the bar that appears click <b>Options<\/b> [a] then activate <b>Auto Merge<\/b>, <b>Split Edges &#038; Face<\/b> and set the <b>Threshold<\/b> as required [b].<\/p>\n<p><a href=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/merge-tool-settings.jpg\" target=\"_blank\" rel=\"noopener\"><img decoding=\"async\" style=\"width: 98.5%; height: auto;\" src=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/merge-tool-settings.jpg\" alt=\"Merge Tool Settings\" width=\"900px\" height=\"500px\" border=\"0\" \/><\/a><br \/>\n<i>Merge options can also be found in the <b>Tool Settings<\/b> bar running along the top of the 3D Viewport in Options [a &#038; b].<\/i><\/p><\/blockquote>\n<p><a href=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/auto-merge.jpg\" target=\"_blank\" rel=\"noopener\"><img decoding=\"async\" style=\"width: 100%; height: auto;\" src=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/auto-merge.jpg\" alt=\"Enable Auto Merge in Sidebar\" width=\"900px\" height=\"500px\" border=\"0\" \/><\/a><br \/>\n<i>The first step to merging edges at an intersection is to enable <b>Auto Merge<\/b> [3] in the Sidebar [2] and then <b>Split Edges &#038; Faces<\/b> [4] &#8211; the two settings activate the function.<\/i><\/p>\n<h3><span class=\"ez-toc-section\" id=\"moveedit-edge\"><\/span>Move\/Edit Edge<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><b>Step 2<\/b>: Once the <b>Auto Merge<\/b> and <b>Split Edges &#038; Faces<\/b> are enabled, for Blender to split and merge edges and faces make sure they are appropriately aligned and then manipulate a connected edge in some way [5] &#8211; this can be as simple as moving an edge that&#8217;s part of an intersected group, or selecting an edge and subdividing it, anything that essentially alerts Blender to the intersections location which, depending on the <b>Threshold<\/b> set, is then split, vertices inserted and elements merged within range of the manipulation [6].<\/p>\n<blockquote><p><b>Design note<\/b>: Auto Merge does not automatically join intersections immediately upon being enabled, it has to be prompted through User action, which avoids issues caused by inadvertently merging every intersection found &#8211; excess geometry creation for example.<\/p><\/blockquote>\n<blockquote style=\"background-color: #fc0; color: #000;\"><p><b>Important<\/b>: Auto Merge is not a Boolean operation, it does not remove unwanted geometry &#8211; despite proper vertex placement [c], faces may not split and\/or merge as expected so some coincidental or co-planar surfaces may remain [d], some clean up then being necessary.<\/p>\n<p><a href=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/merge-clean-up.jpg\" target=\"_blank\" rel=\"noopener\"><img decoding=\"async\" style=\"width: 98.5%; height: auto;\" src=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/merge-clean-up.jpg\" alt=\"Merge clean up\" width=\"900px\" height=\"500px\" border=\"0\" \/><\/a><br \/>\n<i>Because merging in this context is selective and not a Boolean operation, it may mean some unwanted structure remains in place [c] despite the mesh being correctly processed [d], requiring some clean up after the fact.<\/i><\/p>\n<p>In <b>Face<\/b> select mode the &#8216;active&#8217; selection [e] is biased towards merging into surrounding structure [f]. This means the order, or which face essentially cuts\/merges into others, is determined by surface selection order, the last face being the active object around which merging occurs. To change the bias, change selection order.<\/i><\/p>\n<p><a href=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/merge-active-selection.jpg\" target=\"_blank\" rel=\"noopener\"><img decoding=\"async\" style=\"width: 98.5%; height: auto;\" src=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/merge-active-selection.jpg\" alt=\"Merge Order\" width=\"900px\" height=\"500px\" border=\"0\" \/><\/a><br \/>\n<i>When merging faces the order surfaces merge together is biased towards the active object, even in a group &#8211; the last element selected [e] becomes the focal point around which merging occurs, so one face might cut into another [f] or vice versa depending on selection order.<\/i><\/p><\/blockquote>\n<p><a href=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/manipulate-merge.jpg\" target=\"_blank\" rel=\"noopener\"><img decoding=\"async\" style=\"width: 100%; height: auto;\" src=\"https:\/\/www.katsbits.com\/images\/tutorials\/merge\/manipulate-merge.jpg\" alt=\"Manipulating to prompt merge\" width=\"900px\" height=\"500px\" border=\"0\" \/><\/a><br \/>\n<i>Auto Merge doesn&#8217;t merge intersections by default, they need to be prompted so Blender knows which elements to be included in the action &#8211; typically simply moving or manipulating a selection [5] is enough to initiate the  operation, which then places the necessary vertices [6].<\/i><\/p>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":4662,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[34,230],"tags":[795,671,674,403,410,794],"class_list":["post-4651","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blender","category-tutorials","tag-auto-merge","tag-boolean","tag-intersect","tag-merge","tag-merge-vertices","tag-sidebar"],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/www.katsbits.com\/codex\/wp-json\/wp\/v2\/posts\/4651","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.katsbits.com\/codex\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.katsbits.com\/codex\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.katsbits.com\/codex\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.katsbits.com\/codex\/wp-json\/wp\/v2\/comments?post=4651"}],"version-history":[{"count":27,"href":"https:\/\/www.katsbits.com\/codex\/wp-json\/wp\/v2\/posts\/4651\/revisions"}],"predecessor-version":[{"id":5028,"href":"https:\/\/www.katsbits.com\/codex\/wp-json\/wp\/v2\/posts\/4651\/revisions\/5028"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.katsbits.com\/codex\/wp-json\/wp\/v2\/media\/4662"}],"wp:attachment":[{"href":"https:\/\/www.katsbits.com\/codex\/wp-json\/wp\/v2\/media?parent=4651"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.katsbits.com\/codex\/wp-json\/wp\/v2\/categories?post=4651"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.katsbits.com\/codex\/wp-json\/wp\/v2\/tags?post=4651"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}