From f8a0aadaff58a62e05686f642eec5c1606e942d2 Mon Sep 17 00:00:00 2001
From: Frederick Roy <froy@lnrobo.com>
Date: Thu, 19 Mar 2026 17:08:22 +0900
Subject: [PATCH] fix when giving 0 as index for fixFirstNodesWithUntil

---
 .../controller/InterventionalRadiologyController.inl   | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/BeamAdapter/component/controller/InterventionalRadiologyController.inl b/src/BeamAdapter/component/controller/InterventionalRadiologyController.inl
index 5a21797c4..c5417a77f 100644
--- a/src/BeamAdapter/component/controller/InterventionalRadiologyController.inl
+++ b/src/BeamAdapter/component/controller/InterventionalRadiologyController.inl
@@ -1121,14 +1121,20 @@ void InterventionalRadiologyController<DataTypes>::fillInstrumentCurvAbsTable(co
 template <class DataTypes>
 void InterventionalRadiologyController<DataTypes>::fixFirstNodesWithUntil(unsigned int firstSimulatedNode)
 {
+    l_fixedConstraint->clearConstraints();
+
+    if (firstSimulatedNode == 0)
+    {
+        d_indexFirstNode = 0;
+        return;
+    }
+
     WriteAccessor<Data<VecCoord> > xMstate = *getMechanicalState()->write(sofa::core::vec_id::write_access::position);
     WriteAccessor<Data<VecCoord> > xrestMstate = *getMechanicalState()->write(sofa::core::vec_id::write_access::restPosition);
     WriteAccessor<Data<VecDeriv> > vMstate = *getMechanicalState()->write(sofa::core::vec_id::write_access::velocity);
 
     // set the position to startingPos for all the nodes that are not simulated
     const auto& startPos = d_startingPos.getValue();
-    // and add a fixedConstraint
-    l_fixedConstraint->clearConstraints();
     for(unsigned int i=0; i<firstSimulatedNode-1 ; i++)
     {
         xMstate[i] = startPos;