diff --git a/embodichain/lab/sim/sim_manager.py b/embodichain/lab/sim/sim_manager.py
index 35ae05b5..1eb607ad 100644
--- a/embodichain/lab/sim/sim_manager.py
+++ b/embodichain/lab/sim/sim_manager.py
@@ -1085,6 +1085,12 @@ def add_robot(self, cfg: RobotCfg) -> Robot | None:
 
             cfg.fpath = cfg.urdf_cfg.assemble_urdf()
 
+            if cfg.solver_cfg is not None:
+                if isinstance(cfg.solver_cfg, dict):
+                    for key, value in cfg.solver_cfg.items():
+                        if hasattr(value, "urdf_path") and value.urdf_path is None:
+                            value.urdf_path = cfg.fpath
+
         if uid is None:
             uid = os.path.splitext(os.path.basename(cfg.fpath))[0]
             cfg.uid = uid