Surface shapes are defined by using the asphere equation:
R is the radius of curvature. Use negative values to flip orientation.
K is the conic constant.
| K | Surface Shape |
| K < -1 | Hyperbola |
| K = -1 | Parabola |
| -1 < K < 0 | Ellipse (prolate spheroid) |
| K = 0 | Sphere |
| K > 0 | Ellipse (oblate spheroid) |
A2, A4, A6, A8 describe the deviation of the surface from the axially symmetric quadric surface specified by R and K. Note: If K=-1 then A2 is redundant.
To specify a Flat Surface leave all Shape parameters blank.
Specify the component size using the Radius parameter.
Stop parameter allows specifying a lip at the edge of a lens.
Three surface behaviors are allowed:
- Lens: Rays hitting the surface will be refracted.
- Mirror: Rays hitting the surface will be reflected.
- Grating: Rays hitting the surface will be diffracted.