AutoCAD offers many tools that help users create precise geometric designs with ease. While most people rely on the CIRCLE command to draw circles, you can also use the POLYGON command to create a circle-like shape or draw a circle through the help of polygon options. This is especially useful when you want to define a circle based on its center and radius or when working with inscribed and circumscribed shapes.
In this guide, you’ll learn how to draw a circle using the POLYGON command options and how polygons connect with the geometry of a circle in AutoCAD.
1. Understanding the Relationship Between Circles and Polygons
A polygon can be:
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Inscribed in a circle (polygon fits inside a circle)
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Circumscribed around a circle (circle fits inside a polygon)
AutoCAD allows you to draw polygons using both methods. Once created, these polygons help you:
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Visualize circular boundaries
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Control the circle diameter precisely
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Construct circles from polygon geometry
2. Using the POLYGON Command to Draw a Circle-Like Shape
Step-by-Step: Drawing a Circle Using a Polygon
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Type
POLYGONinto the command line and press Enter. -
AutoCAD will ask:
“Enter number of sides:”-
For circle-like geometry → use a high number (e.g., 50, 100, or 200 sides)
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The more sides you choose, the more it resembles a perfect circle.
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AutoCAD will ask:
“Specify center of polygon:”-
Click a point or type coordinates.
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Next, AutoCAD asks:
“Inscribed in circle” or “Circumscribed about circle”:-
Inscribed → polygon fits inside the circle
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Circumscribed → polygon surrounds the circle
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Enter the radius of the circle you want.
This will generate a very smooth polygon that acts like a circle—useful for visualizations and certain design tasks.
3. Drawing a Circle Through a Polygon
If you want to draw an actual CIRCLE that touches (passes through) the polygon:
Method 1: Use Polygon Radius to Create a Real Circle
After drawing the polygon using the Inscribed option:
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The radius you entered equals the circle radius.
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Type CIRCLE, choose the same center point, enter the same radius.
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Now you have a perfect circle passing through the polygon’s vertices.
Method 2: Use Polygon Vertices to Define Circle
If you want the circle to pass through three vertices:
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Draw the polygon.
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Type CIRCLE.
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Choose the 3-Point option.
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Click any three vertices of the polygon.
AutoCAD will draw a precise circle passing through those points.
4. When to Use Polygon-Based Circle Construction
This technique is helpful when:
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Designing gears, mechanical parts, or architectural shapes
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Creating circular patterns with equal divisions
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Working with multi-sided symmetrical objects
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Learning geometric construction in AutoCAD
It ensures accuracy when circles must relate perfectly to polygon edges or vertices.
5. Tips for Better Results
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Use ORTHO mode for cleaner alignment.
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Turn on OSNAP (Object Snap) for selecting vertices accurately.
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If you want a smoother “circle,” increase polygon sides (50+).
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Use Properties panel to adjust radius or sides later if needed.
Conclusion
Drawing a circle through the POLYGON command in AutoCAD is simple once you understand how inscribed and circumscribed polygons relate to circles. Whether you want a polygon-based circular outline or need a precise circle through polygon vertices, AutoCAD offers flexible options that improve your design accuracy and workflow.
