At 2.74\scripts\addons\io_scene_fbx\__init__,py line 480,
```
global_matrix = (Matrix.Scale(self.global_scale, 4) *
axis_conversion(to_forward=self.axis_forward,
to_up=self.axis_up,
).to_4x4())
```
axis_conversion from io_utils.py line 268,
```
def axis_conversion(from_forward='Y', from_up='Z', to_forward='Y', to_up='Z'):
```
is called with unspecified from_forward and from_up. This is to convert from Blender's coordinates to the coordinate system of the FBX file. But Bender's forward is -Y. So using the default parameter produces incorrect behavior.
There is at least one other piece of code which is incorrect in a matched way to try compensate for this, and will also have to be changed. At:
2.74\scripts\addons\io_scene_fbx\export_fbx_bin.py line 2856:
```
"axis_forward": '-Z',
```
even though Unity3D uses +Z forward.