{"id":5517,"date":"2026-08-18T10:45:09","date_gmt":"2026-08-18T09:45:09","guid":{"rendered":"https:\/\/www.luso-cad.com\/?p=5517"},"modified":"2026-08-18T15:20:10","modified_gmt":"2026-08-18T14:20:10","slug":"closeline","status":"publish","type":"post","link":"https:\/\/www.luso-cad.com\/en\/closeline\/","title":{"rendered":"4 Ways to Quickly Close Lines in LusoCAD with the CLOSELINE Command"},"content":{"rendered":"
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When working on CAD drawings, it is common to find lines, polylines or arcs that appear to form a closed area but actually have small gaps between their endpoints. This type of situation can cause problems in subsequent operations, especially when using commands such as BO<\/code> (Boundary), hatch creation, area calculation or region generation.<\/p>

As we saw in other productivity articles on LusoCAD, small tools can save a lot of time on repetitive tasks. The command CLOSELINE<\/strong> it was created precisely to solve this problem, making it possible to identify and automatically close segments that should be connected.<\/p>

In this article, we explore how the CLOSELINE command works and in which situations it can help you prepare cleaner and more precise drawings.<\/p>

What Does the CLOSELINE Command Do?<\/h1>

The command:<\/p>

CLOSELINE<\/span><\/div>

enables quick identification of unclosed endpoints in selected lines, polylines and arcs.<\/p>

After identifying the unconnected points, LusoCAD attempts to automatically close the gaps according to the object geometry.<\/p>

This avoids time-consuming manual corrections and reduces the possibility of errors in subsequent operations.<\/p><\/div>

\"CLOSELINE<\/p>

Why is it Important to Close Geometries?<\/h1>

Many LusoCAD tools depend on the existence of closed boundaries.<\/p>

For example:<\/p>

  • Creation of hatches<\/li>
  • Area calculation<\/li>
  • Command BO<\/code><\/li>
  • Creation of regions<\/li>
  • 3D modelling operations<\/li>
  • Geometric information extraction<\/li><\/ul>

    A small gap between two lines can stop these tools from working properly.<\/p>

    How to Use the CLOSELINE Command<\/h1>

    On the command line, type:<\/p>

    CLOSELINE<\/span><\/div>

    Next:<\/p>

    1. Select the required objects<\/li>
    2. Confirm the selection<\/li>
    3. LusoCAD analyses the open ends<\/li>
    4. Compatible elements are automatically closed<\/li><\/ol>

      The process is quick and usually takes only a few clicks.<\/p>

      How Does the Automatic Closer Work?<\/h1>

      Behaviour varies depending on the geometry of the selected objects.<\/p><\/div>

      \"\"<\/p>

      Parallel Lines<\/h2>

      When two lines are parallel to each other, normally there is no natural point of intersection.<\/p>

      In these cases, LusoCAD can create a connection via an arc to close the existing opening.<\/p>

      This allows you to create a continuous outline without the need to redraw the elements.<\/p>

      Non-Parallel Lines<\/h2>

      When objects are not parallel, the system attempts to extend them until they find a common point.<\/p>

      Depending on the situation, LusoCAD can:<\/p>

      • Extend segments<\/li>
      • Create automatic intersections<\/li>
      • Trim excess parts<\/li><\/ul>

        The result is a closed and consistent boundary.<\/p>

        Compatible Object Types<\/h1>

        The command supports various object combinations.<\/p>

        Line + Line<\/h2>
        Line<\/span><\/div>

        One of the most common situations.<\/p>

        Ideal for correcting gaps created during manual drawing.<\/p>

        Line + Polyline<\/h2>
        Line \u2192 Polyline<\/span><\/div>

        Allows closing mixed elements without the need to convert objects.<\/p>

        Line + Arc<\/h2>
        Line \u2192 Arc<\/span><\/div>

        Very useful for mechanical details and complex geometric drawings.<\/p>

        Polyline + Polyline<\/h2>
        Polyline \u2192 Polyline<\/span><\/div>

        Makes it easy to create closed boundaries from independent polylines.<\/p>

        How to Know if an Object Can Be Closed?<\/h1>

        Whilst using the command, LusoCAD automatically analyses the selected elements.<\/p>

        If an object cannot be closed, it will not be marked as valid.<\/p>

        In this situation, the following message may appear:<\/p>

        The selected segment is invalid. Please select again.<\/span><\/div>

        This normally indicates that:<\/p>

        • Geometry does not allow automatic closing<\/li>
        • The segments are too far apart<\/li>
        • The objects do not have an appropriate geometric relationship<\/li><\/ul>

          In these cases it may be necessary to make some manual adjustments before using the control again.<\/p>

          When should you use CLOSELINE?<\/h1>

          This tool is especially useful in situations such as:<\/p>

          Preparation for Hatching<\/h3>

          Before using:<\/p>

          Hatch<\/span><\/div>

          It is important to ensure that the boundaries are fully closed.<\/p>

          Setting Boundaries<\/h3>

          When using:<\/p>

          BO<\/span><\/div>

          Any gap can prevent the correct creation of the boundary.<\/p>

          Calculation of Areas<\/h3>

          As we saw in the article on area calculation in LusoCAD, the boundaries must be properly closed to ensure correct results.<\/p>

          Clearing of Received Drawings<\/h3>

          Imported drawings or those received from third parties often contain small connection gaps that can be fixed quickly with CLOSELINE.<\/p>

          Advantages of the CLOSELINE Command<\/h1>

          Among the main benefits are:<\/p>

          • Fewer manual corrections<\/li>
          • Greater speed in the preparation of drawings<\/li>
          • Reduction of errors in hatching and boundaries<\/li>
          • Better geometry quality<\/li>
          • Higher productivity in complex projects<\/li><\/ul>

            For users who regularly work with plans, construction details or mechanical drawings, this tool can represent a significant saving in time.<\/p>

            Conclusion<\/h1>

            The command CLOSELINE<\/strong> LusoCAD is a simple yet extremely useful tool for identifying and fixing open ends in lines, polylines and arcs. By automating the geometry closing process, it helps prepare drawings for subsequent operations such as hatching, area calculation and region creation.<\/p>

            If you frequently work with closed boundaries or receive drawings from different sources, it's worth adding the CLOSELINE<\/code> to your day-to-day toolkit.<\/p><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>","protected":false},"excerpt":{"rendered":"

            Learn how to use the CLOSELINE command in LusoCAD to automatically close lines, polylines and arcs, improving drawing quality and productivity.<\/p>","protected":false},"author":4,"featured_media":5524,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-5517","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.luso-cad.com\/en\/wp-json\/wp\/v2\/posts\/5517","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.luso-cad.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.luso-cad.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.luso-cad.com\/en\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.luso-cad.com\/en\/wp-json\/wp\/v2\/comments?post=5517"}],"version-history":[{"count":14,"href":"https:\/\/www.luso-cad.com\/en\/wp-json\/wp\/v2\/posts\/5517\/revisions"}],"predecessor-version":[{"id":5537,"href":"https:\/\/www.luso-cad.com\/en\/wp-json\/wp\/v2\/posts\/5517\/revisions\/5537"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.luso-cad.com\/en\/wp-json\/wp\/v2\/media\/5524"}],"wp:attachment":[{"href":"https:\/\/www.luso-cad.com\/en\/wp-json\/wp\/v2\/media?parent=5517"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.luso-cad.com\/en\/wp-json\/wp\/v2\/categories?post=5517"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.luso-cad.com\/en\/wp-json\/wp\/v2\/tags?post=5517"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}