# Circle¶

class `rhino3dm.``Circle`
`Circle`(radius)

Initializes a circle with center (0,0,0) in the world XY plane.

Parameters: radius (float) – Radius of circle, should be a positive number.
`Circle`(center, radius)

Initializes a circle parallel to the world XY plane with given center and radius.

Parameters: center (rhino3dm.Point3d) – Center of circle. radius (float) – Radius of circle (should be a positive value).
`IsValid`

bool: A valid circle has radius larger than 0.0 and a base plane which is must also be valid.

`Radius`

float: Gets or sets the radius of this circle. Radii should be positive values.

`Diameter`

float: Gets or sets the diameter (radius * 2.0) of this circle. Diameters should be positive values.

`Center`

rhino3dm.Point3d: Gets or sets the center point of this circle.

`Normal`

rhino3dm.Vector3d: Gets the normal vector for this circle.

`Circumference`

float: Gets or sets the circumference of this circle.

`PointAt`(t)

Parameters: t (float) – Parameter of point to evaluate. The point on the circle at the given parameter. rhino3dm.Point3d
`TangentAt`(t)

Parameters: t (float) – Parameter of tangent to evaluate. The tangent at the circle at the given parameter. rhino3dm.Vector3d
`DerivativeAt`(derivative, t)

Determines the value of the Nth derivative at a parameter.

Parameters: derivative (int) – Which order of derivative is wanted. t (float) – Parameter to evaluate derivative. Valid values are 0, 1, 2 and 3. The derivative of the circle at the given parameter. rhino3dm.Vector3d
`ClosestPoint`(testPoint)

Gets the point on the circle which is closest to a test point.

Parameters: testPoint (rhino3dm.Point3d) – Point to project onto the circle. The point on the circle that is closest to testPoint or Point3d.Unset on failure. rhino3dm.Point3d
`Translate`(delta)

Moves the circle.

Parameters: delta (rhino3dm.Vector3d) – Translation vector. True on success, False on failure. bool
`Reverse`()

Reverse the orientation of the circle. Changes the domain from [a,b] to [-b,-a].

Return type: void
`ToNurbsCurve`()

Constructs a nurbs curve representation of this circle. This amounts to the same as calling NurbsCurve.CreateFromCircle().

Returns: A nurbs curve representation of this circle or None if no such representation could be made. rhino3dm.NurbsCurve
`Encode`()