diff --git a/urls.py b/urls.py
index a06e7cd..0b71a68 100644
--- a/urls.py
+++ b/urls.py
@@ -137,7 +137,7 @@ trogglepatterns = [
 #   Cave description pages
     path('cave_debug',  cave_debug,  name="cave_debug"), 
     re_path(r'^newcave/$', edit_cave, name="newcave"),
-    re_path(r'^cave/3d/(?P<cave_id>[^/]+)$', cave3d, name="cave3d"),
+    re_path(r'^cave/3d/(?P<cave_id>[^/]+).3d$', cave3d, name="cave3d"),
 
     #re_path(r'^cave/description/([^/]+)/?$', caves.caveDescription), #!!!BAD, local links fail..
     #re_path(r'^cave/(?P<cave_id>[^/]+)/?$', caves.cave, name="cave"), # used only in testing !? XXXXXXXXXXXXXXXXXXXXXXXXXX