Function Syntax: CenterAreaCentroid / get_centroid / MostInnerPoint2 Version: 1.1 Date: 20.06.2026 6:38:50PM https://forums.augi.com/showthread.php?5641-Getting-the-centroid-of-closed-polyline https://forums.augi.com/showthread.php?5641-Getting-the-centroid-of-closed-polyline 📍 CenterAreaCentroid AutoCAD AutoLISP utility for placing an internal center-area point or centroid label from selected drawing geometry. Useful for CAD geometry checking, closed-boundary annotation, centroid marking, and quick drafting automation inside AutoCAD or Civil 3D. 🚀 Function Syntax Run CenterAreaCentroid in the AutoCAD command line. The dialog lets the user choose between Center Area and Centroid. 📘 SEO Friendly Description 📐 CenterAreaCentroid is an AutoCAD AutoLISP geometry tool that calculates useful internal reference locations for selected objects. 🎯 The Center Area option uses the MostInnerPoint2 workflow to place an AutoCAD POINT inside a closed boundary. 🧭 The Centroid option uses the get_centroid workflow to convert a selected polyline into a REGION, read the centroid, and place a CENTROID text label. 🧩 This tool is useful for CAD technicians, Civil 3D users, drafting teams, and engineers who need fast area-center and centroid annotation workflows. ✅ Functionalities 🪟 DCL dialog selection - opens a temporary dialog named CenterAreaCentroid Options. 📌 Center Area mode - places a POINT at an internal calculated location of a closed object. 🧭 Centroid mode - places a CENTROID text label at the geometric centroid of the selected polyline-derived region. 🔄 Last option memory - remembers the last selected radio option during the AutoCAD session. 📐 Closed polyline and spline support - inner-point calculation supports closed AcDbPolyline and planar closed AcDbSpline objects. 🧱 REGION centroid workflow - uses AutoCAD REGION conversion and ActiveX centroid extraction. 🟢 Point creation - creates a POINT entity at the calculated internal location using color index 3. 📝 Text annotation - creates middle-center justified TEXT labelled CENTROID at the centroid coordinate. 🧩 Helper Functions • writeCACDCL writes the temporary DCL dialog file. • radioCACDCL controls dialog loading, radio selection, OK, Cancel, and session option memory. • MostInnerPoint calculates an inner point using offset refinement for closed planar geometry. • MostInnerPoint2 selects the object and creates the POINT result. • get_centroid creates a region, reads its centroid, and writes the CENTROID label. 📊 Result ✅ The final result is either an internal AutoCAD POINT for a closed area or a CENTROID text label placed at the calculated centroid position. This improves AutoCAD area annotation, centroid checking, drawing review, and geometric drafting workflows. ⚠️ Important Notes The Center Area workflow requires supported closed geometry. The Centroid workflow requires geometry that can be converted into an AutoCAD REGION. The routine depends on Visual LISP COM functions and should be run inside AutoCAD with ActiveX support available. 🏷️ Tags 🏷️ AutoCAD 🏷️ AutoLISP 🏷️ Civil 3D 🏷️ Center Area 🏷️ Centroid 🏷️ Polyline 🏷️ Closed Polyline 🏷️ Spline 🏷️ Region 🏷️ Area Tools 🏷️ CAD Geometry 🏷️ Drafting Automation 🏷️ DCL Dialog 🏷️ Visual LISP