# urx.element_geometry - moduleus/urx GitHub Wiki

Geometry of an ultrasonic element.

## Parameters

Parameter |
Datatype |
Description |
---|---|---|

perimeter |
Array of vector3d |
Define the element perimeter. The last element of perimeter is automatically connected to the first. |

## Notes

### Perimeter

The *perimeter* is a list of 3D-coordinates expressed in its own cartesian coordinate system. It is assumed that the acoustic center of the element is at origin $O = (0, 0, 0)$. If an element of the probe does not face $Z = (0, 0, 1)$, it should be rotated using the *element.transform* attribute.

The following example represents an *element.perimeter*:

```
element : {
perimeter : [
[3, -2, 0],
[-3, -2, 0],
[-2, 3, 0],
[2, 3, 0]
]
}
```