To define surface to ambient radiation:
- Do one of the following:
- In the Simulation study tree, right-click Thermal Loads
and select Radiation 
.
- Click .
- Click Radiation (Simulation toolbar).
The Radiation PropertyManager appears.
- Under Type, click Surface to ambient.
- In the graphics area, select the desired faces.
To select all faces exposed to outside at once, click Select all exposed faces. To delete a face, right-click the face and select Delete.
- Under Radiation parameters, do the following:
-
Select the desired unit and type a value for the Ambient Temperature
. To associate a time curve with the ambient temperature, click Use Time Curve 
then click Edit, and import or define a time curve. The value of the ambient temperature at any time instant is calculated by multiplying the specified ambient temperature value by the corresponding Y value of the time curve. This option is available for transient thermal studies only.
-
Set the Emissivity . To associate a temperature curve with the emissivity, click Use Temperature Curve
then click Edit, and import or define a temperature curve. The value of the emissivity at a given temperature is calculated by multiplying the specified emissivity value by the corresponding Y value of the temperature curve.
- Set the View Factor
.
- Click
.