add argument for minimum mass

Author: jtigue-bdai

source/isaaclab/isaaclab/envs/mdp/events.py

@@ -323,6 +323,11 @@ def __init__(self, cfg: EventTermCfg, env: ManagerBasedEnv):
                 "Randomization term 'randomize_rigid_body_mass' does not support operation:"
                 f" '{cfg.params['operation']}'."
             )
+        if cfg.params["min_mass"] < 1e-6:
+            raise ValueError(
+                "Randomization term 'randomize_rigid_body_mass' does not support 'min_mass' less than 1e-6 to avoid"
+                " physics errors."
+            )
 
     def __call__(
         self,
@@ -333,6 +338,7 @@ def __call__(
         operation: Literal["add", "scale", "abs"],
         distribution: Literal["uniform", "log_uniform", "gaussian"] = "uniform",
         recompute_inertia: bool = True,
+        min_mass: float = 1e-6,
     ):
         # resolve environment ids
         if env_ids is None:
@@ -360,7 +366,7 @@ def __call__(
         masses = _randomize_prop_by_op(
             masses, mass_distribution_params, env_ids, body_ids, operation=operation, distribution=distribution
         )
-        masses = torch.clamp(masses, min=1e-6)  # ensure masses are positive
+        masses = torch.clamp(masses, min=min_mass)  # ensure masses are positive
 
         # set the mass into the physics simulation
         self.asset.root_physx_view.set_masses(masses, env_ids)