A device and method for performing fast grid-based refining segmentation (FGRS) for video-based point cloud compression (V-PCC) is proposed. The method may include dividing a space of a three-dimensional (3D) point cloud into multiple grids to derive multiple voxels, searching for filled voxels including one or more points, searching for surrounding voxels which are filled voxels within a certain radius from each of the filled voxels, and searching for edge voxels which are present at a segment edge among all the filled voxels. The method may also include calculating smooth scores for surrounding voxels of each edge voxel and calculating a smooth score sum which is a smooth score for the edge voxel on the basis of the smooth scores of the surrounding voxels of the edge voxel, and updating a projection plane index (PPI) for each individual point in the edge voxel using the calculated smooth score sum.