applyImpulse to object: vector: NaN ?

[spikethea]

When I apply a impulse force to my cube object. the cube disappears. console logging shows that as soon as applyImpulse is added that the vector of the object becomes NaN.

heres the line

         cube.applyImpulse(1, new THREE.Vector3( 0.1, 0, 0 ))

[spikethea]

Also, why is there such a lack of documentation for this? Is physijs rarely used nowadays?