MoveAxisToObjectCenter.py

import c4d

def main():
    
    ps = op.GetAllPoints() #Points in Local coordinates List
    m = op.GetMg() #Object Global Matrix

    center = op.GetMp() #Local coordinates center: https://tinyurl.com/wed88cn
    rad = op.GetRad() # Geometry radius: https://tinyurl.com/tb6vn64
    
    center -= c4d.Vector(0,rad.y,0) #Move down axis to lowest point. Comment this line to keep axis in a center 
    
    center *= m #Convert to Global coordinates center

    new_m = c4d.Matrix(m) #Copy matrix
    new_m.off = center #Change its center

    loc_m = ~new_m * m #Get local matrix

    op.SetAllPoints([loc_m.Mul(p) for p in ps])
    op.SetMg(new_m)
    
    op.Message(c4d.MSG_UPDATE)
    c4d.EventAdd()


if __name__ == '__main__':
    main()