specifying a directory name for a dimension should work now

overviewer_core/settingsValidators.py

@@ -182,8 +182,20 @@ def validateStr(s):
     return str(s)
 
 def validateDimension(d):
-    if d in ["nether", "overworld", "end", "default"]:
-        return d
+    # these are provided as arguments to RegionSet.get_type()
+    pretty_names = {
+        "nether": "DIM-1",
+        "overworld": None,
+        "end": "DIM1",
+        "default": 0,
+    }
+    
+    try:
+        return pretty_names[d]
+    except KeyError:
+        if d.startswith("DIM"):
+            return d
+    
     raise ValidationException("%r is not a valid dimension" % d)
 
 def validateOutputDir(d):