don't break build for soft dependencies

.travis.yml

@@ -96,8 +96,11 @@ script:
 # install most deps here
 - pip install -q .[easy]
 
-# xxhash only has linux wheels and triangle is compiled
-- pip install -q triangle xxhash
+# xxhash only has linux wheels and is a soft dependancy
+- pip install -q xxhash || true
+# triangle is compiled, sometimes fails 
+# on Python 3.7, and is a soft dependency
+- pip install -q triangle || true
 
 # run main tests
 # -W default means that warnings only prints the

tests/test_gltf.py

@@ -40,7 +40,7 @@ def test_units(self):
             extents = scene.extents.copy()
             as_in = scene.convert_units('in')
             # should all be exactly mm -> in conversion factor
-            assert g.np.allclose(extents / as_in.extents, 25.4)
+            assert g.np.allclose(extents / as_in.extents, 25.4, atol=.001)
 
 
 if __name__ == '__main__':

trimesh/version.py

@@ -1 +1 @@
-__version__ = '2.33.38'
+__version__ = '2.33.39'