diff --git a/urdf_model/include/urdf_model/link.h b/urdf_model/include/urdf_model/link.h
index e470b43..f43e6e8 100644
--- a/urdf_model/include/urdf_model/link.h
+++ b/urdf_model/include/urdf_model/link.h
@@ -50,7 +50,7 @@ namespace urdf{
 class Geometry
 {
 public:
-  enum {SPHERE, BOX, CYLINDER, MESH} type;
+  enum {SPHERE, BOX, CYLINDER, MESH, SDF} type;
 
   virtual ~Geometry(void)
   {
@@ -112,6 +112,23 @@ class Mesh : public Geometry
   };
 };
 
+class SDF : public Geometry
+{
+public:
+  SDF() { this->clear(); type = Geometry::SDF; };
+  std::string filename;
+  Vector3 scale;
+
+  void clear()
+  {
+    filename.clear();
+    // default scale
+    scale.x = 1;
+    scale.y = 1;
+    scale.z = 1;
+  };
+};
+
 class Material
 {
 public: