An object that can't fall – zero-gravity – but which can be struck and affected by a strike

(sundialsvc4) #1

I’m trying to create an object – a rotating metal ring or cage – whose (X,Y,Z) position cannot change.

The object should not be influenced by gravity, nor can it be displaced in space by anything striking it.

But it can be struck, and, when it is struck, not only do things bounce off of it but its rotation is affected by the strike. (For instance, if a ball strikes the leading edge of the ring as it’s spinning towards the ball, the ring’s rotation should be slowed down by the impact … but the ring should not change position in space.)

I expected that rigid body would allow me to define more-than-one constraint on an object but this does not appear to be the case. What I intuitively expected to be able to do was to clamp the object in 3D space while defining other constraints (hinge …) to define its movement. (The rings are attached to one another like a gyroscopic gymbal.)

(omgold) #2

Shouldn’t a single ‘Point’ constraint suffice for that purpose? Move the pivot points of the ring, the constraint empty and the second (dummy/passive) object for the constraint to the same place. That should allow the ring to rotate freely but not translate.

(sundialsvc4) #3

Can that "second dummy/passive object be an empty, or does it have to be a mesh?