diff --git a/MathLib/Point3dWithID.h b/MathLib/Point3dWithID.h
index d25cc7eb8415722ed8ef2058e2f59989d5e12a15..1bf43197caf08e9abba221e1445e87b25aa39eba 100644
--- a/MathLib/Point3dWithID.h
+++ b/MathLib/Point3dWithID.h
@@ -41,7 +41,7 @@ public:
 	/// the provided id.
 	/// @param coords coordinates of the point
 	/// @param id the id of the object [default: max of std::size_t]
-	Point3dWithID(std::array<double,3> & coords,
+	Point3dWithID(std::array<double,3> const& coords,
 		std::size_t id = std::numeric_limits<std::size_t>::max())
 		: Point3d(coords), _id(id)
 	{}