Bug Fix Loot At

An attempt to help with google-research#197 google-research#198

Created a new function in Kubric core. set_position()

I hope this is helpful xD

kubric/core/objects.py

@@ -123,6 +123,7 @@ def __init__(self, position=(0., 0., 0.), quaternion=None,
                up="Y", front="-Z", look_at=None, euler=None, **kwargs):
     if look_at is not None:
       assert quaternion is None and euler is None
+      self.lookat = look_at
       quaternion = look_at_quat(position, look_at, up, front)
     elif euler is not None:
       assert look_at is None and quaternion is None
@@ -136,6 +137,7 @@ def __init__(self, position=(0., 0., 0.), quaternion=None,
   def look_at(self, target):
     self.quaternion = look_at_quat(self.position, target, self.up, self.front)
 
+
   @property
   def rotation_matrix(self):
     """ Returns the rotation matrix corresponding to self.quaternion."""