What is lacking in Mechanical Engineers today, is the knowledge of how to design mechanisms correctly. Did know that there's a mathematical formula that can be used for all mechanism designs? It's called Gruebler's Count. I found a way to make it practical for all 3D mechanisms. Here's the link if you are interested. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KFB8gMjxDPk.html