[UPROPERTY](Programming/UnrealArchitecture/Reference/Properties)(EditAnywhere, Category="Sort Order")
int32 SortOrderHint
By default, emitters are drawn in the order that they are added to the system. This value will allow you to control the order in a more fine-grained manner. Materials of the same type (i.e. Transparent) will draw in order from lowest to highest within the system. The default value is 0.