Reference Section > Shape Library > Other Shapes

The Asymmetric Trapezium is a flat four sided plate with a horizontal bottom edge and a parallel top edge of a different length. Left Offset sets where the top edge starts, so the top edge can sit anywhere along the bottom edge or beyond it, and the two sloping sides can lean at different angles – one of them can be vertical, or both can lean the same way. It is sized by the two edge lengths, the height and the offset of the top edge from the bottom left corner, which suits drawings dimensioned that way. The corners are always sharp.

It appears in the shapes library under Basic Shapes and Other Shapes. It has no other names (aliases).

Insert point and orientation

The insert point is the bottom left corner. The shape is one closed outline through four corners, in this order:

1.bottom left, at the insert point (0, 0)

2.top left, at (Left Offset, Height)

3.top right, at (Left Offset + Top Width, Height)

4.bottom right, at (Bottom Width, 0)

The bottom edge runs to the right along X for Bottom Width and the top edge is Height above it. The left side leans to the right when Left Offset is positive, is vertical when it is 0, and overhangs the insert point to the left when it is negative. The right side is vertical when Left Offset + Top Width equals Bottom Width; when it is greater, the top right corner overhangs the bottom right corner.

With the default sizes the corners are at (0, 0), (50, 75), (125, 75) and (125, 0) mm, so the default part has a vertical right side and a sloping left side.

Properties

Lengths are in the current units (mm or inches). The defaults are the same size whichever units are set; the default is shown below in mm, with inches in brackets.

Property	Description	Default
Left Offset	Horizontal distance along X from the bottom left corner to the top left corner. Positive moves the top edge to the right. Negative values are allowed and put the top left corner to the left of the insert point. There is no practical limit on the value.	50 mm (2 in)
Top Width	Length of the top edge along X, measured to the right from the top left corner. 0 brings the two top corners together and makes the shape a triangle. Must be 0 or more; the property page refuses negative values.	75 mm (3 in)
Bottom Width	Length of the bottom edge along X, from the insert point to the bottom right corner. 0 brings the two bottom corners together and makes the shape a triangle. Must be 0 or more; the property page refuses negative values.	125 mm (5 in)
Height	Perpendicular distance along Y between the bottom and top edges. Must be 0 or more; the property page refuses negative values.	75 mm (3 in)

The dimensions drawn on the shape are Left Offset (horizontal, from the bottom left corner to the top left corner, drawn above the shape), Top Width (above the top edge), Bottom Width (below the bottom edge) and Height (vertical, beside the right side).

Limits

Left Offset accepts any value; its lower limit is -1E208 and its upper limit is the largest 32-bit integer, so there is no practical limit. Top Width, Bottom Width and Height have a lower limit of 0 and the same upper limit. The property page refuses a negative value in any of these three and keeps the previous value. The refusal message begins Please enter a valid number, followed by the property name and the allowed range. Text that is not a number is refused with the same message.

The shape itself has no checks beyond these limits. The red Warning: Cannot build shape from these parameters bar is shown only if building the outline raises an error. Some values do not give a useful part:

•Height 0 flattens the shape onto a line.

•Top Width and Bottom Width both 0 leave a single line from the insert point to the top left corner.

For a trapezium that is symmetric about its centre line, set Left Offset to (Bottom Width − Top Width) / 2, or use the Trapezium shape.

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.