DiSMech (Discrete Simulation for Mechanics of Slender Structures) is an open-source simulation software being developed at the Structures-Computer Interaction Lab at UCLA in collaboration with Boston University and Carnegie Melon University, to simulate complex soft structures that can be modeled as flexible rods, plates, or shells, or a combination thereof. Based on discrete-differential geometry, It uses the popular discrete elastic rods theory to simulate rods and two different discrete elastic shell models to simulate thin plates and shells.