Circle

The default Part.makeCircle(r)() produces a circular line on the XY plane with radius r. (A one dimensional object embedded in a two dimensional plane in three dimensional space). The function Part.Circle(r)() does essentially the same thing but takes arguments for the center, normal and radius, and has to be converted to a shape object.

c = Part.makeCircle(5)
#Part.show(c)
c2 = c.copy()
testEqual(c, c2)
testNotEqual(c, Part.makeCircle(6))

testEqual(c, Part.Circle(o, z, 5).toShape() )

A circle has attributes that can be checked as follows.

print(c.Curve.Radius == 5.0)
print(c.Curve.Center == o )
print(c.Curve.Axis   == z )

True
True
True

Within its plane, a circle is symmetic around its center, so this circle can be rotated any number of degrees around the Z-axis and produces an equal object

c2.rotate(o, z, 180)
testEqual(c, c2)
c2.rotate(o, z, 90)
testEqual(c, c2)
c2.rotate(o, z, 33)
testEqual(c, c2)

but translation produces an object that is not equal.

c2.translate(Vector(0,0,10))
testNotEqual(c, c2)

This circle is centered at the origin and is on the plane normal to z axis. A circle has one edge and no faces, properties that can be checked.

C = Part.makeCircle(10)
print( len(C.Edges) )
print( len(C.Faces) )
print( len(C.Solids) )

1
0
0

When constructing a face (two dimensional object) from a circle (one dimensional object) it is usually important that the circle is not a partial circle, that is, it forms a complete closed loop. This is also a property that can be checked.

print( C.isClosed() )

True

A face can be constructed by filling in the circle. For some reason this needs to be converted to a wire first.

C2 = Part.Face(Part.Wire(C))
print( C2.ShapeType )
print( len(C2.Faces) )
print( len(C2.Solids) )
#Part.show(C2)

Face
1
0