I know you’re all good SOLIDWORKS user and use sub-assemblies all the time…right? Sub-assemblies improve performance because SOLIDWORKS doesn’t need to solve all the mates of the sub-assemblies. The less top-level mates the better you will be.
Well let’s say you need to show some motion of a sub-assembly but you get the message that it is fully defined.
You can make the sub-assembly behave like a top level assembly. You will need to RMB on the sub-assembly and choose Properties. The Component Properties window will open up and in the bottom right corner, there is an option to “Solve as…”. You will want to choose “Flexible”.
Enjoy your new “flexibility”.