I am trying to create a robot arm with bones and skeletons. I want to drag the arm in screen space and it should respect each joints.
I have seen physics joint but for my use case I believe I do not need them. How can I model this with bones and skeletons. I need to have various kind of joints like ball joint , socket joint, hinge joint(as in the arm) etc.
Can you please provide a very minimal example with just ball joint?
You may want to check out Bones and Skeletons | Babylon.js Documentation (babylonjs.com)
Ahhhhhhh you beat me to it lol 
I have seen the topic on bones and skeletons. But i wonder how can i model the different kind of joints. I.e Contrain the bones
search for the babylon classes that you think are of interest, and you will find many fruitful examples. the search indexing is pretty terrible on the backend, so just try to search for terms that will be in a playground as the leading word.
these docs and playground prob more relevant to you
but also… i saw they have physics v3 plugin in the works, so idk. maybe if you need something like NOW , use three. but, i’d say if you want it to work a year from now, use babylon for sure.
It’s not v3, it’s all improvements to v2 
If you want to go deeper into this subject, you’ll have to research about inverse kinematics Inverse kinematics - Wikipedia as that’s what ultimately moves the IK controller
lol, thats good
