ik极向量控制器应该往哪里放——where a ik handle's pole vector should live

本文介绍了一种使用Python和Maya API通过矢量运算来确定关节中间定位器位置的方法。该方法通过计算三个关键点的矢量关系，找到正确的极轴定位器的位置。

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import pymel.core as pm

def place_correct_pole_locator(joint1, joint2, joint3):
    joint_start_position = pm.xform(joint1, q = 1, ws = 1, rp = 1)
    joint_mid_position = pm.xform(joint2, q = 1, ws = 1, rp = 1)
    joint_end_position = pm.xform(joint3, q = 1, ws = 1, rp = 1)

    joint_start_vector = pm.dt.Vector(joint_start_position)
    joint_mid_vector = pm.dt.Vector(joint_mid_position)
    joint_end_vector = pm.dt.Vector(joint_end_position)

    start_end_vector = joint_end_vector - joint_start_vector
    start_mid_vector = joint_mid_vector - joint_start_vector

    dotP = start_mid_vector.dot(start_end_vector)
    proj = float(dotP)/float(start_end_vector.length())
    start_end_normal = start_end_vector.normal()

    proj_vector = start_end_normal*proj
    arrow_vector = start_mid_vector - proj_vector
    arrow_vector *= 2
    final_vector = arrow_vector + joint_mid_vector

    locator = pm.spaceLocator()
    locator.t.set(final_vector)

if __name__ == '__main__':
    JOINT_start = 'joint1'
    JOINT_mid = 'joint2'
    JOINT_end = 'joint3' 

    place_correct_pole_locator(JOINT_start, JOINT_mid, JOINT_end)

这个问题困扰我挺长时间，不是问题自身有多难，而是对矢量的运算没搞明白，好吧，说白了，是高中数学没学好，下面是自己最后实现的方式：