Transport to substrate
Evaporation is a very directional deposition method. This means that the deposition process depends very much on the position and orientation of the substrate in relation with the source. A picture was drawn below in order to simplify the calculation of deposition rate. The mass deposited on the a small surface shown in the picture with dark blue ( with the area of: )is:

                                
As it can be seen the deposited mass (i.e film thickness) is proportional with the angles Φ and θ (i.e. orientation and position of the substrate).

Deposition rate
The deposition rate in case of an evaporation process can be calculated by dividing the calculated deposited mass by the density of the material, the area of the substrate and the deposition time, as below and replacing the evaporation rate: