More explicit example error when MeshCat is not installed

Author: stephane-caron

examples/meshcat_shapes.py

@@ -11,9 +11,16 @@
 (and thus meshcat) a dependency of the project.
 """
 
-import meshcat
 import numpy as np
 
+try:
+    import meshcat
+except ModuleNotFoundError as exc:
+    raise ModuleNotFoundError(
+        "This example requires MeshCat. "
+        "It can be installed e.g. by `conda install meshcat-python`"
+    ) from exc
+
 
 def __attach_axes(
     handle: meshcat.Visualizer,

pink/visualization.py

@@ -13,18 +13,18 @@
 def start_meshcat_visualizer(
     robot: pin.RobotWrapper,
 ) -> visualize.MeshcatVisualizer:
-    """Open a MeshCat visualizer in a web browser.
+    """Open a MeshCat visualizer in a Web browser.
 
     Args:
-        robot: Robot wrapper with its initial data.
+        robot: Pinocchio robot wrapper with its model and data.
 
     Returns:
         MeshCat visualizer.
     """
-    viz = visualize.MeshcatVisualizer(
+    visualizer = visualize.MeshcatVisualizer(
         robot.model, robot.collision_model, robot.visual_model
     )
-    robot.setVisualizer(viz, init=False)
-    viz.initViewer(open=True)
-    viz.loadViewerModel()
-    return viz
+    robot.setVisualizer(visualizer, init=False)
+    visualizer.initViewer(open=True)
+    visualizer.loadViewerModel()
+    return visualizer