This paper focuses on the 3D coverage problem in Wireless Sensor Networks employing real-world terrain models. Firstly, we examine the sensing models used in WSN and propose novel deployment strategies. Then, we study the coverage behavior of these heterogeneous deployment strategies under three 3D real-world terrain models. Our purpose is to find answers to questions like which deployment strategy gives the best 3D coverage for a specified 3D terrain and how many sensors are needed to maintain coverage at a specified percentage. Furthermore, on these 3D real-world terrain models we also study the effects of sleeping on coverage. Simulation results demonstrate that for a given terrain type an appropriate deployment strategy can be selected to obtain required 3D coverage level.