|  
	  
		  From the 
			 Thermal section of the 
			 action bar,
			 click
			 Radiation Cavity Approx 
			  .Optional:  
  Enter a descriptive 
	 Name. 
   
				Select one or more faces as the geometry supports in the model. 
				The selected faces must define an enclosed cavity. 
		  Enter the 
			 Emissivity of the selected faces.
		  
		  The emissivity value must be between zero and one.
		   
		   Click 
			 OK.
		   
		
 |