Exporting optical properties

Thermal Model Exchanger exports all the Thermal Desktop thermo-physical properties available in the model, even if some of them are not assigned to mesh elements.

Thermal Model Exchanger (TMX) supports the Basic and Wavelength-Dependent types of Thermal Desktop optical properties.

For regular meshes, the application creates a Simcenter 3D Thermo-Optical Properties - Advanced modeling object for each Thermal Desktop Optical Property and assigns it to the mesh collector.

In Thermal Desktop, the 3D primitives can have a different optical property on each of the six faces of the primitive. Thus, for 3D primitives, the application verifies the Thermal Desktop Optical Property defined on each face of the primitive and follows one of the scenarios listed in the following table.


Scenario	TMX actions
3D primitives with the same optical property on each of the six faces	Creates a Simcenter 3D Thermo-Optical Properties - Advanced modeling object with the Thermal Desktop Optical Property characteristics. Assigns it to the 3D mesh collector that corresponds to the Thermal Desktop primitive.
3D primitives with a different optical property on each of the six faces	Creates a Simcenter 3D Surface Coat mesh with a 2D Null Shell type of Mesh Collector for each surface of the primitives. Creates Simcenter 3D Thermo-Optical Properties - Advanced modeling objects with the Thermal Desktop Optical Property characteristics of each surface of the primitives. Assigns each Simcenter 3D Thermo-Optical Properties - Advanced modeling object to the 2D mesh collector created for each surface of the primitive.

TMX supports constant and field values for the Basic and Wavelength-Dependent types of thermo-optical properties. The following table lists the thermo-optical property value types that are supported by TMX.


	Thermal Desktop optical properties	Thermal Desktop value	Simcenter 3D value
Basic	Solar Absorptivity Infrared Emissivity	Constant	Constant
		Vs. Temperature	Temperature-dependent
		Vs. Angle	Angle-dependent
	Solar Specular Reflectivity Solar Transmissivity Infrared Specular Reflectivity Infrared Transmissivity	Constant	Constant
		Angle	Constant*
	Solar Transmissive Specularity Infrared Transmissive Specularity	Constant	Not supported
		Vs. Angle	Not supported
Wavelength Dependent	Emissivity Specular Reflectivity Transmissivity	Constant	Constant
		Length-dependent	Length-dependent
		Temperature-length	Constant*
	Transmissive Specularity	Constant	Not supported
		Length
		Temperature-length

*When the value is defined as a field in Thermal Desktop, the application exports the value to Simcenter 3D as a constant using the first value of the field and shows a warning in the export summary.

Basic properties

For Thermal Desktop Solar properties, the absorptivity, transmissivity and specularity are all imported directly to the corresponding Simcenter 3D properties.

For Thermal Desktop Infrared properties, the emissivity, transmissivity and specularity are all imported directly to the corresponding Simcenter 3D properties.

The Thermal Desktop Specularity property is called Specular Reflectivity in Simcenter 3D.

In Thermal Desktop the specularity is expressed as a percentage of the total reflectivity, whereas Simcenter 3D requires the absolute value of the specular reflectivity. The following table lists the conversion formulas that TMX applies during the export process.


Property	Conversion formula
Solar Specularity	SSC3D = (1 - A - T) x STD
Infrared Specularity	SSC3D = (1 - E - T) x STD

Where:

SSC3D is the Simcenter 3D specular reflectivity,
A is the absorptivity,
T is the transmissivity,
STD is the Thermal Desktop specularity,
E is the emissivity.

TMX does not export the Thermal Desktop transmissive specularity for both solar and infrared optical properties because this property does not exist in Simcenter 3D.

The Thermal Desktop Refractive Indices Ratio is equivalent to the Index of Refraction in Simcenter 3D. Thermal Desktop allows you specifying solar and infrared Refractive Indices Ratio values while in Simcenter 3D has only one Index of Refraction value for solar and infrared optical properties. During export, TMX specifies the Simcenter 3D Index of Refraction value using the Refractive Indices Ratio value from the Thermal Desktop Solar optical properties. The application also displays a warning message to the export summary when the solar and infrared Refractive Indices Ratio have different values.

Wavelength Dependent properties

For the Thermal Desktop Wavelength-Dependent properties, the emissivity, transmissivity, specularity and refractive indices ratio are all exported directly to the Simcenter3D Thermo-Optical Properties - Advanced modeling object.

TMX does not export the Thermal Desktop transmissive specularity for both Solar and Infrared optical properties because these properties do not exist in Simcenter 3D.