diff --git a/codegen/abstract_facet.hpp.j2 b/codegen/abstract_facet.hpp.j2
index e1fc17c..76985b6 100644
--- a/codegen/abstract_facet.hpp.j2
+++ b/codegen/abstract_facet.hpp.j2
@@ -43,6 +43,8 @@ public:
     // types
     /** integer identifying a type **/
     using typeseq = xo::facet::typeseq;
+    using Copaque = const void *;
+    using Opaque = void *;
     {% for ty in types %}
     /** {{ty.doc}} **/
     using {{ty.name}} = {{ty.definition}};
diff --git a/codegen/genfacet b/codegen/genfacet
index eef2eec..788faf4 100755
--- a/codegen/genfacet
+++ b/codegen/genfacet
@@ -265,8 +265,8 @@ def gen_facet_impl(env,
     # doc section for facet
     facet_doc = '\n'.join(idl['doc'])
 
-    types = facet_idl['types']
-    for ty in types:
+    facet_types = facet_idl['types']
+    for ty in facet_types:
         ty['doc'] = '\n'.join(ty['doc'])
 
     const_methods = facet_idl['const_methods']
@@ -328,6 +328,8 @@ def gen_facet_impl(env,
     # repr_ns2: nested namespace for repr [e.g. scm].
     repr_ns2 = idl['namespace2']
 
+    # local_types: addition type defs (e.g. repr_ns2 != facet_ns2)
+    local_types = idl['local_types']
 
     # iface_facet_repr: IFoo_DRepr
     iface_facet_repr = f'{iface_facet}_{data_repr}'
@@ -379,7 +381,8 @@ def gen_facet_impl(env,
         'router_facet_hpp_j2': 'router_facet.hpp.j2',
         'router_facet_hpp_fname': router_facet_hpp_fname,
         #
-        'types': types,
+        'types': facet_types,
+        'local_types': local_types,
         #
         'const_methods': const_methods,
         #
diff --git a/codegen/iface_facet_repr.hpp.j2 b/codegen/iface_facet_repr.hpp.j2
index 55b7994..221d679 100644
--- a/codegen/iface_facet_repr.hpp.j2
+++ b/codegen/iface_facet_repr.hpp.j2
@@ -46,6 +46,11 @@ namespace {{repr_ns1}} {
             {% for ty in types %}
             using {{ty.name}} = {{facet_ns1}}::{{facet_ns2}}::{{abstract_facet}}::{{ty.name}};
             {% endfor %}
+            using Copaque = {{facet_ns1}}::{{facet_ns2}}::{{abstract_facet}}::Copaque;
+            using Opaque = {{facet_ns1}}::{{facet_ns2}}::{{abstract_facet}}::Opaque;
+            {% for ty in local_types %}
+            using {{ty.name}} = {{ty.definition}};
+            {% endfor %}
             {% if using_dox %}
             ///@}
             /** @defgroup {{repr_ns2}}-{{facet_name_lc}}-{{data_repr_lc}}-methods **/