
Toric Y surface
The Toric Y surface is generated in two steps. First, in the y-z plane a curve is defined by a standard aspheric profile:

Second, this curve is revolved about a vertical (y) axis that intersects the z axis at distance Rtoric from the curve. At its vertex, therefore, the surface has curvature c+2a2 in the y direction and 1/Rtoric in the x direction.
Setting Rtoric to infinity or zero allows the toric surface to be used as an acylinder whose axis is parallel to the x axis.

Parameters
- toricR
- Toric radius of curvature Rtoric
- a2, a4,..., a16
- Aspheric coefficients for surface sag
The Toric Y surface is compatible with the ZEMAX TOROIDAL surface.
Changing a Toric Y surface into a Toric X surface on the surface data editor is a quick ray to rotate the toric by 90 degrees.