Hi Federico. Thanks for your interest in Pyrite. Did you get any kind of error when you used the plugin? This sometimes happens when the mesh can’t be parented to the armature with automatic weights. It’s a limitation of Blender itself. You might try reducing the number of mesh vertexes (perhaps using Blender’s "Merge by Distance’ feature or the Decimate modifier). Fewer "bones" could also help (increasing the numbers in Pyrite’s Simplify Trajectory subpanel).