| Parameter Name | Units | Type | Default | Description |
| X_MAX | double | 0.0 | x half-aperture | |
| Y_MAX | double | 0.0 | y half-aperture | |
| ELLIPTICAL | long | 0 |
is aperture elliptical? | |
| EXPONENT | long | 2 | exponent for boundary equation in elliptical mode. 2 is a true ellipse. | |
| OPEN_SIDE | STRING | NULL | which side, if any, is open (+x, -x, +y, -y) |