Most 3D reconstruction solutions focus on surfaces, and there has not been much research attention paid to the problem of reconstructing 3D scenes made up of large numbers of particles, while the ability to reconstruct such dynamic scenes is potentially very useful in many areas such as colony behavior research and visual modeling. This paper proposes an approach - Relative Epipolar Motion (REM) - towards solving the correspondence problem in stereopsis by utilizing the motion clue. It matches feature trajectories instead of the features themselves as used by existing methods. The proposed method has the following new capabilities: (1) It supports reconstructing dynamic 3D scenes of large number of undistinguishable drifting particles; (2) It is applicable to correspondence establishment for dynamic surfaces made up of repetitive textures; (3) It offers an alternative way to project structured light in active mode for deforming surface reconstruction. Experiment results on both simula...