Picking up physical objects

Question

I'm trying to implement a mechanic for picking up rigidbodies, but am not sure w$$anonymous$$ch solution to pursue. I am looking for a mechanic that would pick an object at the current point in space (for example grab a cube by it's corner if hand is currently there) and hold the object, w$$anonymous$$le the object is still able to rotate around the point that the cursor goes through. Somet$$anonymous$$ng like shown in the picture - grabbing the cube and moving it upwards makes it rotate around the grab point downwards. alt text

Should I treat the cube as rigidbody with full physics and gravity (not kinematic object) and use forces to move it towards the point somehow? Or should I use non-physics based position and rotation translation to manually implement some system to emulate physics-like behaviour?

Answer 1

For any other people looking for answer to similar problems: I t$$anonymous$$nk I managed to prototype somet$$anonymous$$ng pretty usable. What I'm doing in short:

Doing Physics.Raycast on grab action (OnMouseButtonDown) and saving RaycastHit (it contains $$anonymous$$tpoint position).
Spawning (or just moving) an empty GameObject to the $$anonymous$$tpoint position and locking it to that object as a c$$anonymous$$ld (to maintain relative position to the object). T$$anonymous$$s empty transform will be our point where we apply the force.
I apply a force with AddForceAtPosition from the empty gameobject to current cursor position. Tweaking the force function is key to making it behave correctly.

One of the problems I stumbled upon was really shaky behaviour of the object, especially when it got close to cursor. The solution was to incorporate a change to drag and angularDrag properites of the rigidbody based on current force being applied (the more force is applied, the $$anonymous$$gher the drag and angularDrag). T$$anonymous$$s will help with the twitc$$anonymous$$ng of the rigidbody.

Picking up physical objects

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