Double-Surface Elements.

General Description

Double-Surface Elements are restricted with two nonintersecting plane optical surfaces and one or two boundary surfaces. There are two types of double-surface Elements integrated into Application -- Glass Plates and Lenses. Note generally it is the same object. The single difference is predefined shape of Surfaces combined into Double-Surface Element (Plane Surfaces for Glass Plate and Spherical Surfaces for Lens)

The Pivot Point of Double-Surface Element is located at its first surface. As it shown above, 0X axis is longitudinal (optical) one of it. If the Plate or Lens is the solid of revolution, 0X axis is the axis of revolution.

As it illustrated with figure below, hierarchical structure of Double-Surface Elements consists of two Single-Surface Element, Optical Material, and one or two Boundary Properties (depending on shape of Element):

Transformation -- Defines Location and Orientation of Element as a whole. Surface 1 -- Defines properties of first surface of Element (except location and orientation defined with Transformation group of first level of hierarchy). Material -- Defines Optical Material of Element. Surface 2 - Defines properties of first surface of Element (including location and orientation with respect to first one). Boundary Properties 1 -- Defines properties of external boundary of Double-Surface element Boundary Properties 2 -- If applicable, defines properties of internal boundary of Double-Surface Element.

Generally, editing of properties of Double-Surface Element does not differ from Single-Surface Elements. That's why just points specific for Double-Surface Elements will be described here.

To create Double-Surface Element:

• From main menu, choose Insert > Element > Glass Plate or Insert > Element > Lens command, or use context menu of Project docked window to create new Element.
• Set Location of Element.
• Set Orientation of Element.
• Set required Clear Aperture of both Surfaces of Element.
• Set required Optical Material of Element.
• Set required Optical Properties for each Surface of Element (including Boundaries).
• Set required Thermal properties for each Surface of Element (including Boundaries).
• Set desired Visibility Options for each Surface of Element (including Boundaries).

Form-Factor

There is some specificity dealing with affecting form-factor of Double-Surface Element. First, you are able to define Shape of both Surfaces combined into Element (whole set of Simple and Aspherical shapes as well as representation as Triangular Mesh are available). Second, you can affect Boundaries of Double-Surface Element editing Clear Apertures of Surfaces. Finally, you can define Location and Orientation of second Surface with respect to first one affecting thickness of Element and mutual position of its Surfaces. All changes can be provided via editing of parameters within Transformation group of properties of back surface.

To define thickness of Double-Surface Element:

• Within Project docked window, Expand hierarchical tree graph of Double-Surface Element, then expand hierarchical structure of second Surface of Element.
• Choose Transformation group with your pointing device.
• Within Properties docked window, set desired Position x value.

To define eccentricity of back surface with respect to first one:

• Within Project docked window, Expand hierarchical tree graph of Double-Surface Element, then expand hierarchical structure of second Surface of Element.
• Choose Transformation group with your pointing device.
• Within Properties docked window, set desired eccentricity editing Position y and/or Position z values.

Note position of second Surface is defined with respect to first one (i.e. with respect to Pivot Point of Double-Surface Element). So, Coordinate Mode settings will not affect coordinates of second Surface.

To define orientation of back surface with respect to first one:

• Within Project docked window, expand hierarchical tree graph of Double-Surface Element, then expand hierarchical structure of second Surface of Element.
• Choose Transformation group with your pointing device.
• Within Properties docked window, set desired orientation editing Rotation x, Rotation y, and Rotation z values.
• Press Apply button.

Note rotation will be provided around current position of origin of internal coordinate system of back surface.

Optical Material

Note if you will change Optical Material to air, both internal and external boundaries of that Element will be disabled. Element will be considered as a set of sequential surfaces. Example of such kind of Element with corresponding hierarchical structure is shown below:

Optical Material - BAF4 glass from Schott Catalogue	Optical Material - Air from Misc. Catalogue

Nevertheless, you are able to create Double-Surface Element containing internal and external boundaries with air inside. To do it, you have to define air material not from catalogue but with manually printing of "Air" (or any other name you want) as a material name. In this case, Optical Material inside Element will be considered as air but you will able to define Optical Properties of Element's Boundaries. Example of such kind of Element is shown below: