Avoid makeing empty folders for dxfs, stls or png if there are no parts of that type.

scripts/exports.py

@@ -66,9 +66,16 @@ def make_parts(target, part_type, parts = None):
     top_dir = set_config(target, lambda: usage(part_type))
     target_dir = top_dir + part_type + 's'
     deps_dir = target_dir + "/deps"
-    bom_dir = top_dir + "bom"
-    tmp_dir = mktmpdir(top_dir)
 
+    #
+    # Check we have some of this type
+    #
+    bom_dir = top_dir + "bom"
+    all_parts = bom_to_parts(bom_dir, part_type)
+    if not all_parts:
+        return
+
+    tmp_dir = mktmpdir(top_dir)
     if not os.path.isdir(target_dir):
         os.makedirs(target_dir)
 
@@ -83,7 +90,6 @@ def make_parts(target, part_type, parts = None):
     #
     # Decide which files to make
     #
-    all_parts = bom_to_parts(bom_dir, part_type)
     if parts:
         targets = list(parts)           #copy the list so we dont modify the list passed in
     else:

scripts/render.py

@@ -37,19 +37,21 @@ def usage():
     sys.exit(1)
 
 def render(target, type):
-    #
-    # Make the target directory
-    #
     top_dir = set_config(target, usage)
-    tmp_dir = mktmpdir(top_dir)
-    target_dir = top_dir + type + 's'
     bom_dir = top_dir + 'bom'
-    if not os.path.isdir(target_dir):
-        os.makedirs(target_dir)
     #
     # Find all the parts
     #
     parts = bom_to_parts(bom_dir, type)
+    if not parts:
+        return
+    #
+    # Make the target directory
+    #
+    tmp_dir = mktmpdir(top_dir)
+    target_dir = top_dir + type + 's'
+    if not os.path.isdir(target_dir):
+        os.makedirs(target_dir)
     #
     # Read the json bom to get the colours
     #