To perform OOMs generation, two 3D pretraining backbones are utilized, providing efficient and accurate atomic-level representations by leveraging extensive 3D structural information. This enhances the structural validity and convergence speed of generated molecules. The generator in O 2 -GEN is inspired by the VD-GEN , which initializes VPs uniformly within a predefined space. Under the guidance of the 3D pretraining backbone, these VPs are iteratively moved toward regions with high-probability atomic distributions. During generation, the initialization of VPs can be tailored to specific applications by incorporating predefined molecular structures as templates, thereby defining the sampling space.