Creo Flow Analysis > Preprocessing > Defining Physics > Radiation > Conditions > Material Property
  
Material Property
Material properties are volume conditions in the Radiation module that refer to selected volumes.
The material properties appear in the Properties panel when you select a fluid domain under Domains in the Flow Analysis Tree.
A volume is defined as:
Transparent—Passage of radiative heat flux is possible through the transparent volume.
Opaque—Passage of radiative heat flux is not possible through the opaque volume.
Conditions