Function Syntax: DOff / DoubleOffset Version: 1.0 Date: 20.06.2026 6:38:59PM N/A Description 🧩 Double Offset is a Lee Mac AutoLISP utility that offsets a selected curve to both sides using one offset distance or a through point. 🎛️ The command includes options for deleting the source object and placing the new offsets on the current layer or the source layer. 📐 Supported objects include ARC CIRCLE ELLIPSE SPLINE LWPOLYLINE XLINE and LINE. Function Syntax Main command: DoubleOffset Alias: DOff SEO Optimized Overview 📏 Standard distance mode creates one offset at the positive distance and one at the negative distance from the selected curve. 🎯 Through mode calculates the perpendicular distance between the selected through point and the closest point on the source curve and then offsets to both sides by that distance. 🔁 Through mode also provides Multiple so several through points can generate repeated pairs of offsets from the same source object. 🗑️ Erase controls whether the original source entity is deleted after offsetting. 🗂️ Layer controls whether the created offsets retain the source layer or are moved to the current AutoCAD layer. ⚙️ The current OFFSETGAPTYPE value is displayed in the settings summary. ↩️ Each selected object operation is enclosed in an AutoCAD undo mark. Primary Workflow • Run DoubleOffset or DOff. • Enter an offset distance or choose Through Erase or Layer. • Select a supported curve object. • In Through mode pick a through point or choose Multiple for repeated through points. • The routine generates offsets on both sides of the source curve. • The original object is erased when Erase source is set to Yes. • Continue selecting objects or choose Exit. Functionalities ✅ Both side offset - creates positive and negative offsets from one selected curve. ✅ Distance mode - uses the specified numeric offset distance. ✅ Through mode - calculates the offset distance from a picked through point. ✅ Multiple through points - supports repeated through point offsets for one source object. ✅ Erase source option - optionally deletes the source object after successful processing. ✅ Current layer option - can move generated offsets to the active layer. ✅ Source layer option - can retain the original object layer on generated offsets. ✅ Broad curve support - supports ARC CIRCLE ELLIPSE SPLINE LWPOLYLINE XLINE and LINE. ✅ Persistent command settings - keeps Erase and Layer choices in global variables for later command runs. ✅ Undo marks - provides grouped rollback for individual processed objects. Important Commands and Aspects 🧩 DoubleOffset calls the VLA Offset method with positive and negative distances. 🧩 vlax-curve-getClosestPointTo is used to calculate Through mode distance. 🧩 _StartUndo and _EndUndo manage AutoCAD undo marks. Result 🎯 The result is a matched pair of offset curves located on opposite sides of the selected source entity. 🧰 The tool is useful for rapidly generating parallel boundaries center based corridor limits utility envelopes and similar two sided CAD geometry. Important Notes ⚠️ The source identifies Lee Mac as the author and lists version 1-1 dated 12 September 2010. ⚠️ The VLA Offset method can return an error for geometry that cannot produce a valid offset and the source protects those calls with vl-catch-all-apply. ⚠️ The Erase and Layer settings persist during the AutoCAD session. ⚠️ Through mode can set OFFSETDIST to a negative value to represent the AutoCAD Through state. SEO Keywords 🏷️ AutoCAD, 🏷️ Civil 3D, 🏷️ AutoLISP, 🏷️ DoubleOffset, 🏷️ DOff, 🏷️ Lee Mac, 🏷️ Offset both sides, 🏷️ Through offset, 🏷️ Parallel curves, 🏷️ LWPOLYLINE, 🏷️ Spline offset, 🏷️ CAD automation