diff --git a/src/ASM/LR/ASMu3D.C b/src/ASM/LR/ASMu3D.C
index 69e44948..6624e765 100644
--- a/src/ASM/LR/ASMu3D.C
+++ b/src/ASM/LR/ASMu3D.C
@@ -835,7 +835,8 @@ void ASMu3D::evaluateBasis (FiniteElement &el, Matrix &dNdu) const
   }
 }
 
-void ASMu3D::evaluateBasis (FiniteElement &el, Matrix &dNdu, Matrix &C, Matrix &B) const
+void ASMu3D::evaluateBasis (FiniteElement &el, Matrix &dNdu,
+                            const Matrix &C, const Matrix &B) const
 {
   PROFILE2("BeSpline evaluation");
   Matrix N = C*B;
@@ -985,7 +986,7 @@ bool ASMu3D::integrate (Integrand& integrand,
       FiniteElement fe(nBasis);
       fe.iel = iEl+1;
 
-      Matrix   C = bezierExtract[iEl];
+      const Matrix&  C = bezierExtract[iEl];
       Matrix   dNdu, Xnod, Jac;
       Matrix3D d2Ndu2, Hess;
       double   dXidu[3];
diff --git a/src/ASM/LR/ASMu3D.h b/src/ASM/LR/ASMu3D.h
index 07bb7f14..530e04cb 100644
--- a/src/ASM/LR/ASMu3D.h
+++ b/src/ASM/LR/ASMu3D.h
@@ -424,7 +424,8 @@ protected:
   virtual void evaluateBasis(FiniteElement &el, int derivs) const;
 
   //! \brief Evaluate all basis functions and first derivatives on one element
-  virtual void evaluateBasis(FiniteElement &el, Matrix &dNdu, Matrix &C, Matrix &B) const ;
+  virtual void evaluateBasis(FiniteElement &el, Matrix &dNdu,
+                             const Matrix &C, const Matrix &B) const;
 
   //! \brief Evaluate all basis functions and first derivatives on one element
   virtual void evaluateBasis(FiniteElement &el, Matrix &dNdu) const;