diff --git a/navipy/scripts/blend_alongtraj.py b/navipy/scripts/blend_alongtraj.py
index 1a30d5d322dcd5dc3d7054a0d1de84d11f0fa026..fafd2eabd997cb6ff84613648e983ba00cc73fcd 100644
--- a/navipy/scripts/blend_alongtraj.py
+++ b/navipy/scripts/blend_alongtraj.py
@@ -9,13 +9,13 @@ import tempfile
 from navipy.scripts import parser_logger, args_to_logparam
 # Following need to be imported in blender as well
 from navipy.sensors.renderer import BlenderRender
-from navipy.tools.trajectory import Trajectory
+from navipy.trajectories import Trajectory
 from navipy import logger
 
 
 importwithinblender = [
     'from navipy.sensors.renderer import BlenderRender',
-    'from navipy.tools.trajectory import Trajectory',
+    'from navipy.trajectories import Trajectory',
     'from navipy import logger']
 
 
diff --git a/navipy/sensors/renderer.py b/navipy/sensors/renderer.py
index 8894caa8dc464984964ada10bc216252b5af1a18..b0e282d48c5741136c0abf7d70f56e9d09985606 100644
--- a/navipy/sensors/renderer.py
+++ b/navipy/sensors/renderer.py
@@ -59,7 +59,8 @@ class AbstractRender():
             self._logger.exception(msg)
             raise TypeError(msg)
         if not isinstance(trajectory, Trajectory):
-            msg = 'trajectory should be navipy Trajectory'
+            msg = 'trajectory should be {}'.format(Trajectory)
+            msg += 'and not {}'.format(type(trajectory))
             self._logger.exception(msg)
             raise TypeError(msg)
         # Create the directory name if it does