I worked fine without find erros throught the lessons: I mounted mira and visualized it both on Rviz and Gazebo. After I tryed to substitute also the file mira_body_v3.dae with skull_v3.dae and this time too without problems I visualized mira with this new skull.dae file in gazebo and rviz.
At the end, I tryied to import a cad file custom.stl drawed with Creo using Blender to add the coulours and exporting it as custom.dae: in this case happens that if I substitute at the file mira_body_v3.dae this custom.dae file, visualizing mira in Rviz and Gazebo I see mira without this new file. Please, I would to know if I have to add something at custom.dae file to be working.
Thanks in advance for you help