diff --git a/src/ifcopenshell-python/ifcopenshell/util/placement.py b/src/ifcopenshell-python/ifcopenshell/util/placement.py
index 5e161d4f55..10b7e4e9bb 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/placement.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/placement.py
@@ -20,7 +20,10 @@ import numpy as np
 
 
 def a2p(o, z, x):
+    x = x / np.linalg.norm(x)
+    z = z / np.linalg.norm(z)
     y = np.cross(z, x)
+    y = y / np.linalg.norm(y)
     r = np.eye(4)
     r[:-1, :-1] = x, y, z
     r[-1, :-1] = o