Applying Properties

FIGURE 4.7 - Applying a GRIN Property to a Rod

Surface Properties

Surface properties provide physical data for absorptance, scatter (BRDF and BTDF), specular reflectance and specular transmittance. In TracePro, surface properties are identified by name and catalog, and stored in a database.

For detailed descriptions of the components of surface properties such as BRDF and BTDF, see Chapter 7, “Technical Reference”.

To select a property and apply it to a surface, use the following steps:

1.Select a surface in your model. Select from the model window or from the System Tree. You may also select an object to apply the property to all the surfaces of the object.

2.Select Define|Apply Properties and then select the Surface tab.

3.Select a surface property catalog and name from the drop-down lists.

4.For a Table Type Surface Property, a “Reference Data” tab is displayed. You also need to select “Angles Measured in Air” or “Angles Measured in Substrate”. The “Angles Measured in Substrate” option is required only if the raw data used to create the surface property was measured in a medium other than air. For all other cases, the default selection of “Angles Measured in Air” must be used.

5.For a Grating Type Surface Property, you also need to input the values for the Up Direction. The Up Direction is the direction of positive grating orders, and

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Surface Properties

also specifies the zero azimuth direction for anisotropy and asymmetric scatter.

6.For Anisotropic properties or Elliptical BSDF, you need to define the Anisotropic/Asymmetric Axis which orients the 0.0 angle for the Azimuth direction.

7.For Asymmetric Table BSDF, you can choose “Use fixed axis for zero-azimuth asymmetric scatter” allowing you to define the Anisotropic/Asymmetric Axis which orients the 0.0 angle for the Azimuth direction.

8.Click the Apply button.

9.Check the System Tree for the changes you entered.

Note that for neighboring objects, you have the issue of coincident surfaces and the problem of how TracePro handles the situation if different surface properties are applied to these two distinct surfaces. See See “Coincident Surfaces” on page 7.15.

FIGURE 4.8 - Surface property with Reference Data and Anisotropic/ Asymmetric Axis tabs

Using the Surface Property Database

A database filled with predefined surface properties exists as a resource in TracePro. You can view current surface property definitions, add your own catalogs and add your own surface properties using the Surface Property editor (See “Surface Properties” on page 3.23.).

TracePro 5.0 User’s Manual

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