We propose a novel fully automatic technique for roof fitting in 3D point clouds based on sequential importance sampling (SIS).Our approach makes no assumption of the nature (sparse, dense) or origin (LIDAR, image matching) of the point clouds Room Dividers and further distinguishes, automatically, between different basic roof types based on model selection.The algorithm comprises an inherent data parallelism, the lack of which has been a major drawback of most Monte Carlo schemes.A further speedup is achieved by applying a coarse to fine search Food Storage Container Lids within all probable roof configurations in the sample space of roofs.The robustness and effectiveness of our roof reconstruction algorithm is illustrated for point clouds of varying nature.