diff --git a/src/SimState.cpp b/src/SimState.cpp
index 45d9b31..ec99444 100644
--- a/src/SimState.cpp
+++ b/src/SimState.cpp
@@ -130,7 +130,7 @@ bool SimState::init(const nlohmann::json& args_in)
         "solver": "ipc_solver",
         "rigid_body_problem": {
             "rigid_bodies": [],
-            "coefficient_restitution": 0.0,
+            "coefficient_restitution": -1.0,
             "coefficient_friction": 0.0,
             "gravity": [0.0, 0.0, 0.0],
             "collision_eps": 0.0,