Thank you for your reply!
this is not the normal vector but if you add 180 degrees to rx, ry or rz
the hotspot is looking in the opposite direction.
Using the method you taught me, I was able to point hotspotB in the opposite direction of hotspotA. However, I want to place hotspotB in a position opposite of hotspotA and a certain distance away from hotspotA. Therefore, I would like to know how to calculate the coordinates tx, ty, tz.