Hello, I've been working on a animation with the SolidWorks' built-in motion study for a simple assembly.  I started out using distance mates to convey movement, but was told it is better to convert the file into a parasolid to strip mates and use triads for movement which I've done.  I now have issues with lost files that I have to reinsert and have to apply mates again but still getting unusual individual part movements for no reason (was working fine then parts flutter and get out of alignment?)  I understand that SolidWorks Composer is much better for creating animations as it simplifies the file data.  However considering the high cost for composer, I would like to know if anyone has had success with other softwares that cost much less or even free?  Any help will be appreciated. Thank you.