[Closed] align bones

HI, i’m new to maxscript, i’m trying to create a bone system based on some helper already in scene. what I need is to create the end bone. I get the start pos (the parent’s end pos ) but not have the end pos so I set length but the bone is not aligned with his parent. so How can I align? I’ve searched for “align” but I’ve not understand.

another quest: to create a bone I need to set a start pois, an end pos, and the Z direction. how Z direction influence the bone for rig?