I am sure, this works. However, this need the user to create Reference Set for new parts and also set the Reference Sets for every single parts in the assembly. So, to show only solids in the assembly, the user needs to set the relevant Reference Sets for all of the parts in the assembly and sub-assemblies. If he want to show all of the Datums, the user then needs to change the reference sets for all of the parts, and so on. This is only true if the user has already set the Reference Sets for all of the existing and new parts. Am I right or I am missing something here? (I am a new user switching from SW. In SW, you can easily and simply turn different objects On and Off and they stay that way until you change their visibility. I am sure that Reference Sets are extremely powerful for doing lots of tasks. However, I only need to show and hide different objects and nothing more at this stage.)