A new and simplified three-dimensional laser ablation plume model is proposed for simulating particles-obstacles interaction for non-standard pulsed laser deposition (PLD) systems such as the "shadow mask", also known as the "eclipse method", and plasma reflection (PLD/PR). The model is based on the direct Monte-Carlo method and a 3D finite-elements mesh. During deposition, for a significant fraction of the ablated particles, we observed that trajectories are affected by the obstacle even if no direct interaction takes place between the particle and the obstacle. A comparison between experimental and simulation results for thin film deposition by PLD/PR technique is presented. The observed effects regarding ablation plume particles interaction with obstacle and macro-particles are described. (c) 2005 Elsevier B.V. All rights reserved.