Reference Section > Shape Library > Round Shapes

The Flat-Cut Ring (Radius) shape is a ring with a straight flat cut across one side. Its outer and inner circles are centred on the insert point, and a straight cut parallel to X removes the bottom of the ring up to the Cut Height. A shallow flat leaves a ring with a flat edge; a flat deep enough to reach the hole opens the ring into a C shape. The sizes are entered as radii. It was formerly called Partial Ring 2 (Radius).

It appears in the shapes library under Round Shapes. Flat-Cut Ring (Diameter) builds the same part from an OD and ID instead of radii.

Insert point and direction

The centre of both circles is the insert point (Base X, Base Y). The flat is on the –Y side of the centre and runs parallel to X; use Rotation to put it on another side. Cut Height is measured from the lowest point of the outer circle straight up to the flat, so the flat lies at OR – Cut Height below the centre.

What is built depends on how deep the flat is:

•Cut Height 0 – no flat: a full outer circle and the round hole, the same as a plain ring.

•Cut Height up to OR – IR – the flat does not reach the hole. The part is two closed profiles: the round hole, and an outer profile made of the outer arc over the top and the straight flat across the bottom.

•Cut Height more than OR – IR – the flat cuts into the hole. The part is one closed C-shaped profile: the outer arc over the top, a short straight along the flat to the hole, the inner arc back over the top, and a second short straight along the flat back to the start.

OR and IR are dimensioned as radii from the centre; Cut Height is dimensioned vertically from the bottom of the outer circle to the flat.

Properties

Property	Description	Default
Cut Height	Depth of the flat, measured from the lowest point of the outer circle up to the flat (mm or inch). 0 gives no flat. With the defaults the flat (37.5 mm) is deeper than OR – IR (25 mm), so it cuts into the hole and the part is a C shape.	37.5 mm (1.5 in)
IR	Inner radius – the radius of the hole (mm or inch). Must be less than OR.	25 mm (1 in)
OR	Outer radius – the radius of the outer circle (mm or inch).	50 mm (2 in)

Limits

The shape does not check its values against each other. Keep:

•IR greater than 0 and less than OR;

•Cut Height 0 or more;

•Cut Height less than OR + IR, so the flat stays below the top of the hole.

Outside these limits the shape does not refuse the values. The angle calculation is clamped to its valid range, so the flat and the arcs are drawn at the nearest possible positions, and the outline is not the intended part. No warning is shown for these values. Check the drawn shape after changing any of the three values.

Every 2D shape also has the Transform properties (Base X, Base Y, Rotation, Scale, Mirroring X) and the Polar Array properties, listed after the shape's own properties.