Polyline (AutoCAD)
A single AutoCAD entity composed of connected line and/or arc segments with optional widths — the workhorse of clean drafting.
Definition
An AutoCAD polyline is one object containing one or more vertices and the segments between them. Unlike a chain of separate LINE entities, a polyline can carry per-vertex width, can include arc segments (bulges) without breaking entity continuity, and can be filleted, offset, joined, exploded, and stroked along its length. The PLINE command draws them; PEDIT edits them.
Closed polylines have area; open polylines have only length. The LIST command reports both.
Why it matters
Closed polylines are how AutoCAD knows what a room or a plot is for area calculations and hatching. Polyline width is how to draft electrical busbars, plot boundaries, or thick boundary lines without manually offset-and-fill.
Common pitfalls
- Confusing polyline width with linetype/lineweight — they look similar but plot differently.
- Using PEDIT Join with a tolerance too small to capture nearly-coincident endpoints.
- Editing 2D polylines with PEDIT and 3D polylines with 3DPOLY-specific commands by mistake.
This concept is a core structural element of the AutoCAD drafting and engineering environment developed by Autodesk. The original commercial CAD platform — still the lingua franca of DWG-based 2D documentation across AEC, mechanical, and infrastructure work.
Relevant AutoCAD FAQs
❓ Is AutoCAD LT still sold separately?
No. In 2024 Autodesk consolidated AutoCAD LT into the standard AutoCAD subscription at a single price point. New buyers receive the full AutoCAD with specialized toolsets. Existing LT subscribers were migrated. If you see LT listed by a reseller it is either a transitional SKU or a regional exception.
❓ What is the latest DWG file version AutoCAD writes?
AutoCAD 2018+ writes the 'AutoCAD 2018' DWG format, which is current through AutoCAD 2024 and 2025. Newer releases have not (so far) introduced a new DWG version — meaning files travel freely between recent releases. Always SAVEAS to the recipient's release if you know they are older.
❓ Can I install both AutoCAD and AutoCAD specialized toolsets on the same machine?
Yes — and since 2024 they ship together under one subscription. You install AutoCAD plus the specific specialized toolset(s) you need from the Autodesk Desktop App or Account portal. They share the same DWG engine, so cross-toolset workflows work natively.
⚡ Concept Self-Test
🎓 Recommended Practice Lessons
Step-by-step practical exercises and certification-aligned paths chosen by our editors to master this concept:
🌳 Semantic Crossroads & Navigation Pathways
Trunk-Branch-Leaf ModelCore glossary, interactive graph, and domain-wide concept index.
Parent design environments and platforms implementing this method natively.