Drag object in a direction

I have an arrowhelper that I would like to be able to drag in the direction that it is pointing. I am running into issues with converting between pixels and positions. My current code is:

function initDragObjectAlongAxis() {


    window.addEventListener('mousemove', dragObjectAlongAxis, false);

    window.addEventListener('mouseup', stopDragObjectAlongAxis, false);


function dragObjectAlongAxis(e) {


    object.position.z = e.clientY - objectHeight;


function stopDragObjectAlongAxis(e) {


    window.removeEventListener('mousemove', dragObjectAlongAxis, false);

    window.removeEventListener('mouseup', stopDragObjectAlongAxis, false);


initDragObjectAlongAxis() is called from my raycaster. I have not used drag-controls because I need to be able to drag all three dimensions. I am new to three js and any help is appreciated.