Below is the method to define the direction cosine for face 5 in SURF154. If you want to specify a pressure of 100 on face 5 for element 1 at the direction of (3i+4j+12k)/(3*3+4*4+12*12)^0.5 where i,j,k are the unit vectors in x,y and z direction of the global Cartesian coordinate, issue the following command: SFE,1,5,pres,,100,3,4,12 The same formulae can be found in SURF154 in the Element Manual.