Parametric Constraints (AutoCAD)
Geometric and dimensional rules applied to AutoCAD entities so that resizing or moving one drives the rest.
Definition
AutoCAD supports two kinds of constraints: geometric (coincident, parallel, perpendicular, tangent, concentric, equal, fix, horizontal, vertical, smooth, symmetric, collinear) and dimensional (distance, radius, angle, free expression). Constraints are applied via the Parametric ribbon. The CONSTRAINTSETTINGS dialog controls inferencing and display.
Unlike Inventor or SOLIDWORKS, AutoCAD's parametrics are added on top of free-form entities rather than being foundational — most AutoCAD drawings still have no constraints at all.
Why it matters
Constraints are how to draft dimensioned mechanical details whose geometry stays correct under edits, or to build dynamic blocks whose grips can't produce invalid shapes.
Common pitfalls
- Over-constraining and getting 'redundant constraint' warnings.
- Mixing constraints with absolute geometry edits — the latter break the former.
- Forgetting to hide constraint bars before plotting.
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.