diff --git a/include/sdf/Box.hh b/include/sdf/Box.hh
index 4bf5bfa15..228dd5eac 100644
--- a/include/sdf/Box.hh
+++ b/include/sdf/Box.hh
@@ -68,8 +68,10 @@ namespace sdf
     /// \return A reference to a gz::math::Boxd object.
     public: gz::math::Boxd &Shape();
 
-    /// \brief Calculate an return the Mass Matrix values for the Box
-    public: std::optional< gz::math::MassMatrix3d >  MassMatrix(const double density);
+    /// \brief Calculate and return the Mass Matrix values for the Box
+    /// \param[in] density Density of the box in kg/m^3
+    /// \return A std::optional with gz::math::MassMatrix3d object or std::nullopt
+    public: std::optional< gz::math::MassMatrix3d >  MassMatrix(const double _density);
 
     /// \brief Create and return an SDF element filled with data from this
     /// box.
diff --git a/include/sdf/Capsule.hh b/include/sdf/Capsule.hh
index d26662fa0..3348c017d 100644
--- a/include/sdf/Capsule.hh
+++ b/include/sdf/Capsule.hh
@@ -75,8 +75,10 @@ namespace sdf
     /// \return A reference to a gz::math::Capsuled object.
     public: gz::math::Capsuled &Shape();
 
-    /// \brief Calculate an return the Mass Matrix values for the Capsule
-    public: std::optional< gz::math::MassMatrix3d >  MassMatrix(const double density);
+    /// \brief Calculate and return the Mass Matrix values for the Capsule
+    /// \param[in] density Density of the capsule in kg/m^3
+    /// \return A std::optional with gz::math::MassMatrix3d object or std::nullopt
+    public: std::optional< gz::math::MassMatrix3d >  MassMatrix(const double _density);
 
     /// \brief Create and return an SDF element filled with data from this
     /// capsule.
diff --git a/include/sdf/Collision.hh b/include/sdf/Collision.hh
index 349743e39..eaf6da338 100644
--- a/include/sdf/Collision.hh
+++ b/include/sdf/Collision.hh
@@ -83,8 +83,8 @@ namespace sdf
 
     /// \brief Set the density of the collision.
     /// The density of the collision must be unique within the scope of a Link.
-    /// \param[in] _name Density of the collision.
-    public: void SetDensity(const double density);
+    /// \param[in] _density Density of the collision.
+    public: void SetDensity(const double _density);
 
     /// \brief Get a pointer to the collisions's geometry.
     /// \return The collision's geometry.
diff --git a/include/sdf/Cylinder.hh b/include/sdf/Cylinder.hh
index 1395ce5db..37fcbe35f 100644
--- a/include/sdf/Cylinder.hh
+++ b/include/sdf/Cylinder.hh
@@ -75,8 +75,10 @@ namespace sdf
     /// \return A reference to a gz::math::Cylinderd object.
     public: gz::math::Cylinderd &Shape();
 
-    /// \brief Calculate an return the Mass Matrix values for the Cylinder
-    public: std::optional< gz::math::MassMatrix3d >  MassMatrix(const double density);
+    /// \brief Calculate and return the Mass Matrix values for the Cylinder
+    /// \param[in] density Density of the cylinder in kg/m^3
+    /// \return A std::optional with gz::math::MassMatrix3d object or std::nullopt
+    public: std::optional< gz::math::MassMatrix3d >  MassMatrix(const double _density);
 
     /// \brief Create and return an SDF element filled with data from this
     /// cylinder.
diff --git a/include/sdf/Ellipsoid.hh b/include/sdf/Ellipsoid.hh
index 44f85c696..1c945d2bf 100644
--- a/include/sdf/Ellipsoid.hh
+++ b/include/sdf/Ellipsoid.hh
@@ -67,8 +67,10 @@ namespace sdf
     /// \return A reference to a gz::math::Ellipsoidd object.
     public: gz::math::Ellipsoidd &Shape();
 
-    /// \brief Calculate an return the Mass Matrix values for the Cylinder
-    public: std::optional< gz::math::MassMatrix3d >  MassMatrix(const double density);
+    /// \brief Calculate and return the Mass Matrix values for the Ellipsoid
+    /// \param[in] density Density of the ellipsoid in kg/m^3
+    /// \return A std::optional with gz::math::MassMatrix3d object or std::nullopt
+    public: std::optional< gz::math::MassMatrix3d >  MassMatrix(const double _density);
 
     /// \brief Create and return an SDF element filled with data from this
     /// ellipsoid.
diff --git a/include/sdf/Geometry.hh b/include/sdf/Geometry.hh
index fa45e752e..a097250cf 100644
--- a/include/sdf/Geometry.hh
+++ b/include/sdf/Geometry.hh
@@ -212,12 +212,8 @@ namespace sdf
     public: void SetHeightmapShape(const Heightmap &_heightmap);
 
     /// \brief Calculate and return the Mass Matrix values for the Geometry
-    /// \param[in] _xxyyzz A vector 3d representing the diagonal elements
-    /// of the mass matrix
-    /// \param[in] _xyxzyx A vector 3d representing the off-diagonal elements
-    /// of the mass matrix
     /// \param[in] _density The density of the geometry element.
-    /// \return Boolean that indicates whether the calculation was successfull
+    /// \return A std::optional with gz::math::MassMatrix3d object or std::nullopt
     public: std::optional< gz::math::MassMatrix3d > MassMatrix(const double _density);
 
     /// \brief Get a pointer to the SDF element that was used during
diff --git a/include/sdf/Sphere.hh b/include/sdf/Sphere.hh
index 28e9d1ef4..375517c36 100644
--- a/include/sdf/Sphere.hh
+++ b/include/sdf/Sphere.hh
@@ -68,8 +68,10 @@ namespace sdf
     /// not been called.
     public: sdf::ElementPtr Element() const;
 
-    /// \brief Calculate an return the Mass Matrix values for the Cylinder
-    public: std::optional< gz::math::MassMatrix3d >  MassMatrix(const double density);
+    /// \brief Calculate and return the Mass Matrix values for the Sphere
+    /// \param[in] density Density of the sphere in kg/m^3
+    /// \return A std::optional with gz::math::MassMatrix3d object or std::nullopt
+    public: std::optional< gz::math::MassMatrix3d >  MassMatrix(const double _density);
 
     /// \brief Create and return an SDF element filled with data from this
     /// sphere.