5.2 Drawing and Selection Techniques Introduction

4) How to Draw Circle

Tool: Circle Tool (Home\Draw Panel\Circle Drop down)
Command: CIRCLE

There are many methods to draw circle by using combination of different options available in command prompt. These combinations are also available as a tool in Draw panel and you can view and use them by clicking pull down arrow near the circle tool.

We discuss all these methods by using command prompt options but you can perform all these task by using the equivalent tool.
Command prompt options:
1) Specify Center point for Circle: Specify center point (x, y) of a circle to draw circle by using two methods-
a. Radius: Type length or pick a point to specify radius of a circle.

b. Diameter: Type length or pick a point to specify diameter of a circle.

2) 3P (3 Point): Specify three points on the circumference to draw a circle.

3) 2P (2 Point): This method draw circle using two points and the distance between them is used as a diameter of circle. Specify first and second point of a circle’s diameter.

4) Ttr (Tangent Tangent Radius): This method requires two points on objects as Tangent and specified radius to draw circle. If the specified tangent points and radius is unable to draw circle then program use closest point on tangent objects but when closest point is not available then you get an error “Circle does not exists”.

5) Tan, Tan, Tan (Tangent, Tangent, Tangent): This is the same as 3P method but with a difference that this method requires three point as tangent on objects and choose closest from the tangent point if unable to draw circle. Type ‘tan to’ at command prompt and then specify a point on tangent object.

5) How to Draw Arc

Tool: Arc Tool (Home\Draw Panel\Arc Drop down)
Command: ARC

There are many methods to draw arc by using combination of different options available in command prompt. These combinations are also available as a tool in Draw Panel and you can view and use them by clicking pull down arrow near the arc tool.

This time we discuss all these methods by using tools but you can perform all by using the equivalent options.
List of Tools:
1) : Creates arc by specifying 3 points.

2) : Creates an arc by specifying Start, Center and End point. This method creates an arc between Start point and End point using the distance between Start point and Center as Radius. The resulting Arc is always created Counterclockwise from the start point.

3) : This is the same method as previous method with a difference is that End point is determined by specified Angle that uses the specified center point as the vertex (control point) of the arc.

4) : This is the same method as previous with a difference is that End point is determined by specifying the length of a chord between the Start point and the End point of the arc. Specified Length must be less than or equal to diameter of a imaginary circle otherwise Arc cannot be created.

5) : Specify Start point and Endpoint of the arc and included Angle determines the center point and radius of the arc.

6) : Specify Start point and End point of the arc and a Tangent direction and Angle determine the center of the Arc and Arc direction, i.e. clockwise or counterclockwise. You can draw circle on any side by just specifying the side of the arc, i.e. you are not bound to counterclockwise direction as mentioned in previous methods.


7) : Specify Start and End point of the Arc and radius determine the center point of an arc. Arc is drawn counterclockwise and only when the arc is possible between Start and End point with specified radius otherwise no arc is drawn.

8) : This is the same method as Start, Center, End with a difference that Center point is specified before Start point.
9) : This is the same method as Start, Center, Angle with a difference that center point is specified before Start point.
10) : This is the same method as Start, Center, Length with a difference that center point is specified before Start point.
11) : Select this tool or press Enter key in place of Start point of Arc command to draw Arc from the End point of last drawn line or Arc as a Tangent to that object. We need to specify only End point of Arc.

6) How to Draw Ellipse

Tool: Ellipse Tool (Home\Draw Panel\Ellipse Drop down)
Command: ELLIPSE

Ellipse is drawn around two axis called major axis and minor axis. There are different methods to specify length of these axes to create ellipse. These methods are also available as a tool in draw panel and you can view and use them by clicking pull down arrow near the ellipse tool. It is also possible to draw part of ellipse that is called Elliptical Arc.

We discuss all these methods by using tools but you can perform all by using the equivalent options.
List of Tools:
1) : Creates an ellipse by specifying a Center point of an ellipse, End point of first axis (Major axis) and distance to other axis from center point. You can use Angle option instead of distance to determine Minor axis. If angle value is ‘0’ then it will draw circle instead of Ellipse.

2) : In this method First two End points determines the location and length of the major axis and the third point is used as a half length of minor axis from center of major axis. You can use angle option instead of distance to determine minor axis. If the angle value is ‘0’ then it will draw circle instead of Ellipse.

3) : Using this tool you can draw part of ellipse called elliptical arc. To create elliptical arc follow procedure of previous tools and additionally specify Start angle and End angle of required arc. You can use parameter option to determine minor axis using parametric equation p(u) = c+a*cos(u)+b*sin(u), where ‘c’ is the center of the ellipse, ‘a’ and ‘b’ are its major and minor axes.