Several PES sampling methods have achieved good success in weakly bounded complex systems. The autoPES used a guided Monte Carlo grid generation for mid-range sam-pling, and a further statistically guided sampling needs only 120 points to achieve the same accuracy as 491 points sampled by the old Monte Carlo method. The sampling algorithm in the AUTOSURF relies on searching the maximum difference grids of two local interpolating moving least-squares (L-IMLS) models with different degrees of angular basis functions. These sampling algorithms are highly optimized for their corresponding PES models, which enable them to construct intermolecular PES efficiently and automatically.