diff --git a/GSA_Adapter/Convert/ToGsa/_ToGsa.cs b/GSA_Adapter/Convert/ToGsa/_ToGsa.cs
index a8980c6..aa8cf45 100644
--- a/GSA_Adapter/Convert/ToGsa/_ToGsa.cs
+++ b/GSA_Adapter/Convert/ToGsa/_ToGsa.cs
@@ -75,6 +75,8 @@ public static string ToGsaString(this Type type)
                 return "EL";
             else if (type == typeof(RigidLink))
                 return "EL";
+            else if (type == typeof(RigidConstraint))
+                return "RIGID";
             else if (type == typeof(LinkConstraint))
                 return "PROP_LINK";
             else if (type == typeof(Spacer))