Aspheric Surface 2
This surface is similar to the Aspheric Surface above, with added support for elliptical or rectangular decentered annular apertures. The following parameters are used to define the aspheric surface:
| Parameter # | Description | Face Name | Face # |
| 1 | The radius of curvature. If this value is zero, then the curvature is assumed to be zero. | All Faces | 0 |
| 2 | The conic constant k. | All Faces | 0 |
| 3 | The maximum X direction aperture in lens units. | All Faces | 0 |
| 4 | The maximum Y direction aperture in lens units. | All Faces | 0 |
| 5 | The minimum X direction aperture in lens units. This value may be zero. | All Faces | 0 |
| 6 | The minimum Y direction aperture in lens units. This value may be zero. | All Faces | 0 |
| 7 | The X direction aperture decenter in lens units. | All Faces | 0 |
| 8 | The Y direction aperture decenter in lens units. | All Faces | 0 |
| 9 | The "Is Rectangle" flag. Use 0 for elliptical symmetry, 1 for rectangular symmetry. | All Faces | 0 |
| 10-11 | Unused. | All Faces | 0 |
| 12 | The number of terms to use in the aspheric expansion. Ray tracing will be faster if this term is no larger than the highest order non-zero coefficient. | All Faces | 0 |
| 13-249 | The α coefficients on the polynomial expansion. | All Faces | 0 |
Face Numbers: All faces Face 0.
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