API documentation common Construct* features (#164)

* Common Attach* feature doc

Signed-off-by: anindex <[email protected]>

* Refine docs

Signed-off-by: anindex <[email protected]>

Co-authored-by: anindex <[email protected]>
Co-authored-by: Claire Wang <[email protected]>

include/ignition/physics/ConstructEmpty.hh

@@ -26,13 +26,18 @@ namespace ignition {
 namespace physics {
 
 /////////////////////////////////////////////////
+/// \brief This feature constructs an empty world and return its pointer
+/// from the current physics engine in use.
 class ConstructEmptyWorldFeature : public virtual Feature
 {
   public: template <typename PolicyT, typename FeaturesT>
   class Engine : public virtual Feature::Engine<PolicyT, FeaturesT>
   {
     public: using WorldPtrType = WorldPtr<PolicyT, FeaturesT>;
 
+    /// \brief Construct an empty world and attach a given name to it.
+    /// \return
+    ///   The WorldPtrType of the constructed world.
     public: WorldPtrType ConstructEmptyWorld(const std::string &_name);
   };
 
@@ -45,13 +50,18 @@ class ConstructEmptyWorldFeature : public virtual Feature
 };
 
 /////////////////////////////////////////////////
+/// \brief This feature constructs an empty model and return its pointer
+/// from the given world.
 class ConstructEmptyModelFeature : public virtual Feature
 {
   public: template <typename PolicyT, typename FeaturesT>
   class World : public virtual Feature::World<PolicyT, FeaturesT>
   {
     public: using ModelPtrType = ModelPtr<PolicyT, FeaturesT>;
 
+    /// \brief Construct an empty model and attach a given name to it.
+    /// \return
+    ///   The ModelPtrType of the constructed model.
     public: ModelPtrType ConstructEmptyModel(const std::string &_name);
   };
 
@@ -64,13 +74,18 @@ class ConstructEmptyModelFeature : public virtual Feature
 };
 
 /////////////////////////////////////////////////
+/// \brief This feature constructs an empty link and return its pointer
+/// from the given model.
 class ConstructEmptyLinkFeature : public virtual Feature
 {
   public: template <typename PolicyT, typename FeaturesT>
   class Model : public virtual Feature::Model<PolicyT, FeaturesT>
   {
     public: using LinkPtrType = LinkPtr<PolicyT, FeaturesT>;
 
+    /// \brief Construct an empty link and attach a given name to it.
+    /// \return
+    ///   The LinkPtrType of the constructed link.
     public: LinkPtrType ConstructEmptyLink(const std::string &_name);
   };