Place hemi-cube over element Ei
FOR each element Ej ¹ Ei
Fij = 0
FOR each hemi-cube face
Project element onto hemi-cube face
FOR each patch Pk
IF patch covered
Fij = Fij + DFk
ENDIF
ENDFOR
ENDFOR
Fjtotal = Fjtotal + Fiunsent FijRj
Fjunsent = Fjunsent + Fiunsent FijRj
ENDFOR