The Radiation PropertyManager lets you apply surface to ambient or surface-to-surface radiation.
Radiation is used for thermal studies only. For surface-to-surface radiation, you can consider radiation to the ambient (open system) or ignore it (closed system). The program calculates radiation view factors and considers blocking among the selected faces. You can define any number of features with each feature containing a number of faces with the same emissivity. For surface-to-surface radiation, all faces selected in any radiation feature radiate to each other.
Internally, the program divides each face to smaller areas that can radiate to each other if the face is non-planar.