body:cgroup(bits)
bits=body:cgroup()

Set or get body cgroup bits. You have 31 bits, so use 0x7fffffff to set all. These provide simple yes/no collision control between bodies.

cgroup bits are all the groups this body belongs to.
cmask bits are all the groups this body colides with.

body:change_shape(shape)
body:change_shape(shape,mass)

Change the shape assoctiated with this body and optionally change the mass.

body:cmask(bits)
bits=body:cmask()
body:cmask(0x7fffffff)

Set or get body cmask bits. You have 31 bits, so use 0x7fffffff to set all. This body will only colide with another body if the other bodys cgroup has a bit set that is also set in our cmask.

cgroup bits are all the groups this body belongs to.
cmask bits are all the groups this body colides with.

body:force(fx,fy,fz)
body:force(fx,fy,fz,lx,ly,lz)

Apply force fx,fy,fz at world relative location (subtract origin of object) lx,ly,lz which will default to 0,0,0 if not given.

body:gravity(x,y,z)
x,y,z = body:gravity()

Set or get body gravity vector. Fidling with this may be the easiest way for a player to move an object around, it certainly makes it easier to create "magnetic fields" to hover objects above the ground.

body:impulse(fx,fy,fz)
body:impulse(fx,fy,fz,lx,ly,lz)

Apply impulse fx,fy,fz at world relative location (subtract origin of object) lx,ly,lz which will default to 0,0,0 if not given.

body:overlaps()

Get list of bodys that overlap with a ghost body object.

x,y,z=body:support(nx,ny,nz)

Get world location of support point in given direction.

EG the world location that is touching the floor when the direction is up.