diff --git a/modules/python/config/rbt.json b/modules/python/config/rbt.json
index fb024e4adc..2e32af4ce1 100644
--- a/modules/python/config/rbt.json
+++ b/modules/python/config/rbt.json
@@ -26,6 +26,18 @@
           ]
         }
       ],
+      "methods": [
+        {
+          "static": false,
+          "signature": "void registerTypeRaw(const std::string&, const std::function<std::shared_ptr<T>(const std::string &)>)",
+          "keep_alive": [
+            [
+              1,
+              3
+            ]
+          ]
+        }
+      ],
       "acknowledge_pointer_or_ref_fields": [
         "std::map<std::string, std::function<std::shared_ptr<T>(const nlohmann::json&)>>",
         "std::function<std::string(const nlohmann::json&)>"
@@ -222,12 +234,6 @@
           "static": true,
           "signature": "vpRBDriftDetectorFactory& getFactory()",
           "return_policy": "reference",
-          "keep_alive": [
-            [
-              1,
-              0
-            ]
-          ],
           "returns_ref_ok": true
         }
       ]
@@ -238,12 +244,6 @@
           "static": true,
           "signature": "vpObjectMaskFactory& getFactory()",
           "return_policy": "reference",
-          "keep_alive": [
-            [
-              1,
-              0
-            ]
-          ],
           "returns_ref_ok": true
         }
       ]
@@ -254,12 +254,6 @@
           "static": true,
           "signature": "vpRBFeatureTrackerFactory& getFactory()",
           "return_policy": "reference",
-          "keep_alive": [
-            [
-              1,
-              0
-            ]
-          ],
           "returns_ref_ok": true
         }
       ]
diff --git a/modules/tracker/rbt/include/visp3/rbt/vpDynamicFactory.h b/modules/tracker/rbt/include/visp3/rbt/vpDynamicFactory.h
index 56d8f2cab6..52404f3ccf 100644
--- a/modules/tracker/rbt/include/visp3/rbt/vpDynamicFactory.h
+++ b/modules/tracker/rbt/include/visp3/rbt/vpDynamicFactory.h
@@ -53,12 +53,23 @@ class VISP_EXPORT vpDynamicFactory
 #if defined(VISP_HAVE_NLOHMANN_JSON)
   void registerType(const std::string &key, const std::function<std::shared_ptr<T>(const nlohmann::json &)> &function)
   {
-    if (m_jsonBuilders.find(key) != m_jsonBuilders.end()) {
+    if (m_jsonBuilders.find(key) != m_jsonBuilders.end() || m_jsonRawBuilders.find(key) != m_jsonRawBuilders.end()) {
       throw vpException(vpException::badValue, "Type %s was already registered in the factory", key.c_str());
     }
     m_jsonBuilders[key] = function;
   }
 
+  void registerTypeRaw(const std::string &key, const std::function<std::shared_ptr<T>(const std::string &)> function)
+  {
+    if (m_jsonBuilders.find(key) != m_jsonBuilders.end() || m_jsonRawBuilders.find(key) != m_jsonRawBuilders.end()) {
+      throw vpException(vpException::badValue, "Type %s was already registered in the factory", key.c_str());
+    }
+    std::cout << "IN REGISTERING RAW TYPE" << std::endl;
+    m_jsonRawBuilders[key] = function;
+    std::cout << "IN REGISTERING RAW TYPE END" << std::endl;
+
+  }
+
   std::shared_ptr<T> buildFromJson(const nlohmann::json &j)
   {
     const std::string key = m_keyFinder(j);
@@ -66,6 +77,9 @@ class VISP_EXPORT vpDynamicFactory
     if (m_jsonBuilders.find(key) != m_jsonBuilders.end()) {
       return m_jsonBuilders[key](j);
     }
+    else if (m_jsonRawBuilders.find(key) != m_jsonRawBuilders.end()) {
+      return m_jsonRawBuilders[key](j.dump());
+    }
     else {
       return nullptr;
     }
@@ -82,6 +96,8 @@ class VISP_EXPORT vpDynamicFactory
 
 #if defined(VISP_HAVE_NLOHMANN_JSON)
   std::map<std::string, std::function<std::shared_ptr<T>(const nlohmann::json &)>> m_jsonBuilders;
+  std::map<std::string, std::function<std::shared_ptr<T>(const std::string &)>> m_jsonRawBuilders;
+
   std::function<std::string(const nlohmann::json &)> m_keyFinder; //! Function to retrieve the key from a json object
 #endif
 };