Function Syntax: Command Version: 1.0 Date: N/A Description 🧩 DuplicateToNewLayer and CloseParallelPolylines is an AutoCAD and Civil 3D DCL offset utility for creating left and right offsets from selected LINE LWPOLYLINE POLYLINE SPLINE and ARC geometry. 🎛️ The interface combines offset profiles independent left and right distances target layer controls optional source deletion parallel closing optional centerline generation Apply Undo OK and Cancel. 📚 Built in profiles cover Schutzrohr cable channel sizes and DN300 through DN1000 duct bundle configurations. Function Syntax Main command: DuplicateToNewLayer and CloseParallelPolylines SEO Optimized Overview 📐 The current execution workflow asks the user to select one or more compatible curve objects and creates separate right and left offsets through the VLA Offset method. 📚 The profile list automatically fills matched left and right distances for Schutzrohr DN110 cable channel sizes and DN bundle presets. 🗂️ Place offsets on layer enables a filtered non Xref layer list and a Pick Layer From Drawing option. 🧬 When a target layer is enabled the current source moves the original object to that target layer before generating the offsets so the new offsets inherit the same layer. 🗑️ Delete original object can erase the selected source after offset generation. 🔗 Close Parallel Polylines joins one right and one left offset by calculating the shorter endpoint pairing adding two connector lines and using PEDIT Join. ➗ Create centerline polyline can generate a safe sampled centerline by averaging points on the first offset with closest points on the second offset. 📏 The safe centerline currently samples forty intervals along the first offset curve. ↩️ Apply creates one processing pass and keeps the dialog workflow active while Undo reverses the previous Apply operation. ✅ OK runs one processing pass when no Apply has yet been used then closes and commits the current undo group. ❌ Cancel reverses all Apply operations made during the current command session. Primary Workflow • Run DuplicateToNewLayer and CloseParallelPolylines. • Select or edit an offset profile or enter independent Left and Right distances. • Optionally enable target layer assignment and choose a layer through filter list or drawing pick. • Choose whether the original object should be deleted. • Choose Close Parallel Polylines or leave the generated offsets unclosed. • Choose whether a centerline polyline should be generated when closing. • Use Apply and then select one or more LINE LWPOLYLINE POLYLINE SPLINE or ARC objects. • Use Undo to reverse the previous Apply operation. • Use OK to perform a first pass when required and close the dialog. • Use Cancel to roll back Apply operations from the current command. Functionalities ✅ Independent left and right offsets - allows different offset distances on each side. ✅ Engineering profiles - provides preset Schutzrohr cable channel and DN bundle dimensions. ✅ Multiple object selection - accepts LINE LWPOLYLINE POLYLINE SPLINE and ARC geometry. ✅ Filtered layer picker - filters non Xref layers by user entered name text. ✅ Pick layer from drawing - reads the target layer from a selected drawing entity. ✅ Optional source deletion - erases the original after offset generation when enabled. ✅ Parallel closing - adds two endpoint connector lines and joins the new offset pair. ✅ Automatic endpoint pairing - chooses the lower total endpoint connection distance. ✅ Safe centerline - creates a sampled midpoint LWPOLYLINE between the two offsets. ✅ Apply workflow - creates repeated processing passes without closing the tool. ✅ Undo workflow - rolls back the most recent Apply operation. ✅ Cancel rollback - reverses every Apply made during the current command session. ✅ Persistent UI values - keeps profile offsets deletion layer filter selection mode and close options in global variables. Important Commands and Aspects 🧩 DTNLCPP-OffsetResult-DTNLCPP->Enames converts VLA Offset results into AutoCAD entity names. 🧩 DTNLCPP-CreateCenterlineSafe-DTNLCPP samples the offset pair and creates an averaged lightweight polyline centerline. 🧩 DTNLCPP-CloseTwoParallelEntities-DTNLCPP adds endpoint connectors and joins the offset pair. 🧩 DTNLCPP-GetAllLayers-DTNLCPP returns non Xref drawing layers. 🧩 DTNLCPP-DoOffsetOnce-DTNLCPP performs the current object selection and left and right offset processing. Result 🎯 The result is a pair of left and right offset entities for every selected source curve. 🔗 In Close mode a valid one plus one offset pair is connected and joined into closed parallel geometry. ➗ When enabled an additional sampled centerline lightweight polyline is generated between the two offsets. Important Notes ⚠️ The dialog displays a 2 Points selection mode but the current DTNLCPP-DoOffsetOnce-DTNLCPP execution path always calls the multi object selection routine and does not implement a distinct two point processing path. ⚠️ The Unclose Parallel Polylines radio option currently prevents the close action and leaves newly created offsets open rather than actively opening previously closed geometry. ⚠️ When Place offsets on layer is enabled the current implementation changes the source object layer before creating the offsets. ⚠️ Close mode requires exactly one right and one left entity from the VLA Offset result for the selected source object. ⚠️ The current centerline is an approximation based on forty sample intervals and closest point averaging. 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