diff --git a/render_cpp.py b/render_cpp.py
index 87a4774..35c35cf 100644
--- a/render_cpp.py
+++ b/render_cpp.py
@@ -112,7 +112,7 @@ def render_nodes(gltf):
         skin = node["skin"]
         yield f"extern const Skin skin_{skin};"
 
-    node_parents = build_tree(gltf)
+    node_parents, traversal_order = build_tree(gltf)
 
     for node_ix, node in enumerate(gltf.json["nodes"]):
         if "mesh" in node:
@@ -223,7 +223,9 @@ def render_gltf_source(gltf, filename_hpp):
 
 filename = sys.argv[1]
 filename_cpp = sys.argv[2]
+assert filename_cpp.endswith(".cpp")
 filename_hpp = sys.argv[3]
+assert filename_hpp.endswith(".hpp")
 gltf = decode_file(filename)
 
 with open(filename_cpp, "w") as f:
diff --git a/tree.py b/tree.py
index 28619f4..0d8bee3 100644
--- a/tree.py
+++ b/tree.py
@@ -1,5 +1,13 @@
 from gltf import decode_file
 
+def linearize_tree(node_ix, nodes):
+    yield node_ix
+    node = nodes[node_ix]
+    if "children" not in node:
+        return
+    for child_ix in node["children"]:
+        yield from linearize_tree(child_ix, nodes)
+
 def build_tree(gltf):
     parents = {} # from child to parent
 
@@ -10,14 +18,10 @@ def build_tree(gltf):
             assert child_ix not in parents
             parents[child_ix] = node_ix
 
-    for skin in gltf.json["skins"]:
-        seen = set()
-        for joint in skin["joints"]:
-            parent = parents[joint]
-            assert parent in seen or parent not in skin["joints"], (parent, joint, seen)
-            seen.add(joint)
+    root_node_ix, = [i for i in parents.values() if i not in parents]
+    traversal_order = list(linearize_tree(root_node_ix, gltf.json["nodes"]))
 
-    return parents
+    return parents, traversal_order
 
 if __name__ == "__main__":
     import sys