# Principle - Complementarity-based methods assume bodies are perfectly rigid and compute contact forces at each time step to prevent interpenetration based on impulsive dynamics. By this, we mean they use the impusle-momentum equations. - Complementarity-based methods are an alternative to classical [[5b penalty-based methods|penalty-based methods]] that use virtual spring–damper model to apply restoring forces at the point of deepest penetration between bodies in contact [[cite_mylapilliComplementarityTechniquesMinimal2017a]]. - There are [[5a1 Two variants of Complementarity Problem formulation|two variants]] to the complementarity formulation. # Pros - # Cons