diff --git a/xo-object2/CMakeLists.txt b/xo-object2/CMakeLists.txt
index 53046556..ff21115c 100644
--- a/xo-object2/CMakeLists.txt
+++ b/xo-object2/CMakeLists.txt
@@ -76,6 +76,18 @@ xo_add_genfacetimpl(
     OUTPUT_CPP_DIR src/object2
 )
 
+# note: manual target; generated code committed to git
+xo_add_genfacetimpl(
+    TARGET xo-object2-facetimpl-gcobject-float
+    FACET_PKG xo_gc
+    FACET GCObject
+    REPR Float
+    INPUT idl/IGCObject_DFloat.json5
+    OUTPUT_HPP_DIR include/xo/object2
+    OUTPUT_IMPL_SUBDIR number
+    OUTPUT_CPP_DIR src/object2
+)
+
 # note: manual target; generated code committed to git
 xo_add_genfacetimpl(
     TARGET xo-object2-facetimpl-printable-string
diff --git a/xo-object2/idl/IGCObject_DFloat.json5 b/xo-object2/idl/IGCObject_DFloat.json5
new file mode 100644
index 00000000..6120808b
--- /dev/null
+++ b/xo-object2/idl/IGCObject_DFloat.json5
@@ -0,0 +1,15 @@
+{
+    mode: "implementation",
+    includes: [
+        "<xo/gc/GCObject.hpp>",
+        "<xo/alloc2/Allocator.hpp>"
+    ],
+    local_types: [ ],
+    namespace1: "xo",
+    namespace2: "scm",
+    facet_idl: "idl/GCObject.json5",
+    brief: "provide AGCObject interface for DFloat",
+    using_doxygen: true,
+    repr: "DFloat",
+    doc: [ "implement AGCObject for DFloat" ],
+}
diff --git a/xo-object2/include/xo/object2/DFloat.hpp b/xo-object2/include/xo/object2/DFloat.hpp
index ab38d078..a46a990d 100644
--- a/xo-object2/include/xo/object2/DFloat.hpp
+++ b/xo-object2/include/xo/object2/DFloat.hpp
@@ -6,6 +6,7 @@
 #pragma once
 
 #include <xo/alloc2/Allocator.hpp>
+#include <xo/gc/Collector.hpp>
 #include <xo/facet/obj.hpp>
 #include <xo/indentlog/print/ppindentinfo.hpp>
 
@@ -13,6 +14,7 @@ namespace xo {
     namespace scm {
         struct DFloat {
             using AAllocator = xo::mm::AAllocator;
+            using ACollector = xo::mm::ACollector;
             using ppindentinfo = xo::print::ppindentinfo;
             using value_type = double;
 
@@ -27,9 +29,14 @@ namespace xo {
 
             double value() const noexcept { return value_; }
 
+            operator double() const noexcept { return value_; }
+
             bool pretty(const ppindentinfo & ppii) const;
 
-            operator double() const noexcept { return value_; }
+            // GCObject facet
+            std::size_t shallow_size() const noexcept;
+            DFloat * shallow_copy(obj<AAllocator> mm) const noexcept;
+            std::size_t forward_children(obj<ACollector> gc) noexcept;
 
         private:
 
diff --git a/xo-object2/include/xo/object2/IGCObject_DFloat.hpp b/xo-object2/include/xo/object2/IGCObject_DFloat.hpp
deleted file mode 100644
index 58b931bc..00000000
--- a/xo-object2/include/xo/object2/IGCObject_DFloat.hpp
+++ /dev/null
@@ -1,45 +0,0 @@
-/** @file IGCObject_DFloat.hpp
- *
- *  @author Roland Conybeare, Dec 2025
- **/
-
-#pragma once
-
-#include <xo/alloc2/Allocator.hpp>
-#include <xo/gc/Collector.hpp>
-#include <xo/gc/detail/AGCObject.hpp>
-#include <xo/gc/detail/IGCObject_Xfer.hpp>
-#include "DFloat.hpp"
-
-namespace xo {
-    namespace scm { struct IGCObject_DFloat; }
-
-    namespace facet {
-        template <>
-        struct FacetImplementation<xo::mm::AGCObject,
-                                   xo::scm::DFloat>
-        {
-            using ImplType = xo::mm::IGCObject_Xfer
-                <xo::scm::DFloat,
-                 xo::scm::IGCObject_DFloat>;
-        };
-    }
-
-    namespace scm {
-        /* changes here coordinate with:
-         *  IGCObject_Xfer
-         */
-        struct IGCObject_DFloat {
-        public:
-            using AAllocator = xo::mm::AAllocator;
-            using ACollector = xo::mm::ACollector;
-            using size_type = std::size_t;
-
-            static size_type shallow_size(const DFloat & d) noexcept;
-            static DFloat * shallow_copy(const DFloat & d, obj<AAllocator> mm) noexcept;
-            static size_type forward_children(DFloat & d, obj<ACollector> gc) noexcept;
-        };
-    } /*namespace scm*/
-} /*namespace xo*/
-
-/* end IGCObject_DFloat.hpp */
diff --git a/xo-object2/include/xo/object2/number/IGCObject_DFloat.hpp b/xo-object2/include/xo/object2/number/IGCObject_DFloat.hpp
new file mode 100644
index 00000000..c57c89ea
--- /dev/null
+++ b/xo-object2/include/xo/object2/number/IGCObject_DFloat.hpp
@@ -0,0 +1,67 @@
+/** @file IGCObject_DFloat.hpp
+ *
+ *  Generated automagically from ingredients:
+ *  1. code generator:
+ *       [/Users/roland/proj/xo-umbrella2/xo-facet/codegen/genfacet]
+ *     arguments:
+ *       --input [idl/IGCObject_DFloat.json5]
+ *  2. jinja2 template for abstract facet .hpp file:
+ *       [iface_facet_repr.hpp.j2]
+ *  3. idl for facet methods
+ *       [idl/IGCObject_DFloat.json5]
+ **/
+
+#pragma once
+
+#include "GCObject.hpp"
+#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/Allocator.hpp>
+#include "DFloat.hpp"
+
+namespace xo { namespace scm { class IGCObject_DFloat; } }
+
+namespace xo {
+    namespace facet {
+        template <>
+        struct FacetImplementation<xo::mm::AGCObject,
+                                   xo::scm::DFloat>
+        {
+            using ImplType = xo::mm::IGCObject_Xfer
+              <xo::scm::DFloat,
+               xo::scm::IGCObject_DFloat>;
+        };
+    }
+}
+
+namespace xo {
+    namespace scm {
+        /** @class IGCObject_DFloat
+         **/
+        class IGCObject_DFloat {
+        public:
+            /** @defgroup scm-gcobject-dfloat-type-traits **/
+            ///@{
+            using size_type = xo::mm::AGCObject::size_type;
+            using AAllocator = xo::mm::AGCObject::AAllocator;
+            using ACollector = xo::mm::AGCObject::ACollector;
+            using Copaque = xo::mm::AGCObject::Copaque;
+            using Opaque = xo::mm::AGCObject::Opaque;
+            ///@}
+            /** @defgroup scm-gcobject-dfloat-methods **/
+            ///@{
+            // const methods
+            /** memory consumption for this instance **/
+            static size_type shallow_size(const DFloat & self) noexcept;
+            /** copy instance using allocator **/
+            static Opaque shallow_copy(const DFloat & self, obj<AAllocator> mm) noexcept;
+
+            // non-const methods
+            /** during GC: forward immdiate children **/
+            static size_type forward_children(DFloat & self, obj<ACollector> gc) noexcept;
+            ///@}
+        };
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end */
\ No newline at end of file
diff --git a/xo-object2/src/object2/DFloat.cpp b/xo-object2/src/object2/DFloat.cpp
index 52940efe..7fc0bfbf 100644
--- a/xo-object2/src/object2/DFloat.cpp
+++ b/xo-object2/src/object2/DFloat.cpp
@@ -9,6 +9,7 @@
 namespace xo {
     using xo::facet::typeseq;
     using xo::print::ppdetail_atomic;
+    using std::size_t;
 
     namespace scm {
         DFloat *
@@ -25,6 +26,30 @@ namespace xo {
         {
             return ppdetail_atomic<double>::print_pretty(ppii, value_);
         }
+
+        size_t
+        DFloat::shallow_size() const noexcept
+        {
+            return sizeof(DFloat);
+        }
+
+        DFloat *
+        DFloat::shallow_copy(obj<AAllocator> mm) const noexcept
+        {
+            DFloat * copy = (DFloat *)mm.alloc_copy((std::byte *)this);
+
+            if (copy)
+                *copy = *this;
+
+            return copy;
+        }
+
+        size_t
+        DFloat::forward_children(obj<ACollector>) noexcept
+        {
+            return shallow_size();
+        }
+
     } /*namespace scm*/
 } /*namespace xo*/
 
diff --git a/xo-object2/src/object2/IGCObject_DFloat.cpp b/xo-object2/src/object2/IGCObject_DFloat.cpp
index be4849ac..ef4214a7 100644
--- a/xo-object2/src/object2/IGCObject_DFloat.cpp
+++ b/xo-object2/src/object2/IGCObject_DFloat.cpp
@@ -1,46 +1,39 @@
 /** @file IGCObject_DFloat.cpp
  *
- *  @author Roland Conybeare, Dec 2025
- **/
+ *  Generated automagically from ingredients:
+ *  1. code generator:
+ *       [/Users/roland/proj/xo-umbrella2/xo-facet/codegen/genfacet]
+ *     arguments:
+ *       --input [idl/IGCObject_DFloat.json5]
+ *  2. jinja2 template for abstract facet .hpp file:
+ *       [iface_facet_any.hpp.j2]
+ *  3. idl for facet methods
+ *       [idl/IGCObject_DFloat.json5]
+**/
 
-#include "IGCObject_DFloat.hpp"
-#include "xo/alloc2/alloc/AAllocator.hpp"
-#include "xo/facet/obj.hpp"
-#include <cstddef>
+#include "number/IGCObject_DFloat.hpp"
 
 namespace xo {
-    using xo::mm::AAllocator;
-    using xo::facet::obj;
-    using xo::facet::typeseq;
-    using std::size_t;
-
     namespace scm {
-        size_t
-        IGCObject_DFloat::shallow_size(const DFloat &) noexcept
+        auto
+        IGCObject_DFloat::shallow_size(const DFloat & self) noexcept -> size_type
         {
-            return sizeof(DFloat);
+            return self.shallow_size();
         }
 
-        DFloat *
-        IGCObject_DFloat::shallow_copy(const DFloat & src,
-                                       obj<AAllocator> mm) noexcept
+        auto
+        IGCObject_DFloat::shallow_copy(const DFloat & self, obj<AAllocator> mm) noexcept -> Opaque
         {
-            DFloat * copy = (DFloat *)mm.alloc_copy((std::byte *)&src);
-
-            if (copy)
-                *copy = src;
-
-            return copy;
+            return self.shallow_copy(mm);
         }
 
-        size_t
-        IGCObject_DFloat::forward_children(DFloat & src,
-                                           obj<ACollector>) noexcept
+        auto
+        IGCObject_DFloat::forward_children(DFloat & self, obj<ACollector> gc) noexcept -> size_type
         {
-            return shallow_size(src);
+            return self.forward_children(gc);
         }
 
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end IGCObject_DFloat.cpp */
+/* end IGCObject_DFloat.cpp */
\ No newline at end of file
diff --git a/xo-object2/src/object2/object2_register_facets.cpp b/xo-object2/src/object2/object2_register_facets.cpp
index b9a8d3ac..efbb2a08 100644
--- a/xo-object2/src/object2/object2_register_facets.cpp
+++ b/xo-object2/src/object2/object2_register_facets.cpp
@@ -6,7 +6,7 @@
 #include "object2_register_facets.hpp"
 
 #include <xo/object2/list/IGCObject_DList.hpp>
-#include <xo/object2/IGCObject_DFloat.hpp>
+#include <xo/object2/number/IGCObject_DFloat.hpp>
 #include <xo/object2/IGCObject_DInteger.hpp>
 #include <xo/object2/string/IGCObject_DString.hpp>
 
diff --git a/xo-object2/src/object2/object2_register_types.cpp b/xo-object2/src/object2/object2_register_types.cpp
index a7e95da2..9c6a9196 100644
--- a/xo-object2/src/object2/object2_register_types.cpp
+++ b/xo-object2/src/object2/object2_register_types.cpp
@@ -6,7 +6,7 @@
 #include "object2_register_types.hpp"
 
 #include "list/IGCObject_DList.hpp"
-#include "IGCObject_DFloat.hpp"
+#include "number/IGCObject_DFloat.hpp"
 #include "IGCObject_DInteger.hpp"
 #include "string/IGCObject_DString.hpp"
 
diff --git a/xo-object2/utest/X1Collector.test.cpp b/xo-object2/utest/X1Collector.test.cpp
index f100f38e..330db905 100644
--- a/xo-object2/utest/X1Collector.test.cpp
+++ b/xo-object2/utest/X1Collector.test.cpp
@@ -8,7 +8,7 @@
 #include "DList.hpp"
 #include "object2_register_types.hpp"
 
-#include "IGCObject_DFloat.hpp"
+#include "number/IGCObject_DFloat.hpp"
 #include "list/IGCObject_DList.hpp"
 
 #include <xo/gc/Collector.hpp>