Nuke Python 动画

这部分讲如何搞定动画

设置关键帧

关键帧knob是关键，设置knob来接受动画

    node = nuke.createNode(' blur' )
    k = node['size']
    k.setAnimated()

完成此步骤后就可以用 setValue和setValueAt来设置关键帧了

    k.setValue( 5 ) // 在当前帧设置值为5
    k.setValueAt( 55, 10)
    k.setValueAt( 66, 100 ) 在10,100帧设置值为 55和66

    k.setValueAt( 77, 100, 0 )
    k.setValueAt( 88, 100, 1 ) 如果knob是数组，那么设置在第100帧设置 第一组为 77， 第二组为88

删除关键帧

查看一个knob是否为动画

    node = nuke.createNode( 'Blur')
    k = node['size']
    k.isAnimated()

如果有动画或者表达式动画就返回true

    k.hasExpression()

判断是否 有表达式

获取knob的动画曲线

    animCurve = k.animation( 0 )
    animCurve = k.animation( 1 )

获取一个knob内全部动画曲线

    allCurves = k.animations()

打印动画曲线中的所有值

    for key in animCurve.keys():
        xValue = key.x
        yValue = key.y
        print 'ket at %s has value %s' % ( xValue, yValue)

清除动画曲线中的所有值

    for curve in k.animations():
        curve.clear()

例子

bake动画

这段脚本将所有knob以及附带的表达式bake到关键帧动画里面，首先创建获取帧范围的循环，并在节点间循环

    def bakeSelectNodes():
        ret = nuke.getFramesAndViews(' bake curves in selected nodes?', '%s-%s' % (nuke.root().firstFrame(), nuke.root().lastFrame() ) )

这会弹出对话框来，如下：

判断frame是否可用

    def bakeSelectedNodes():
        ret = nuke.getFramesAndViews( 'bake curves in selelcted nodes?', '%s-%s' % ( nuke.root().firstFrame(), nuke.root().lastFrame() ))
        if not ret:
            return
        fRange = nuke.FrameRange( ret[0] )
        views = ret[1]

在节点运行bakeExpressionKnobs遍历拷贝

    def bakeSelectedNodes():
        ret = nuke.getFramesAndViews('bake curves in selected node', '%s-%s' % ( nuke.root().firstFrame(), nuke.root().lastFrame() ))
        if not ret:
            return
        fRange = nuke.FrameRange( ret[0] )
        views = ret[1]

        for n in nuke.selectedNodes():
            bakeExpressionKnobs(n, fRange.first(), fRange.last(), fRange.increment(), views)

辅助函数
getCurves 返回给定knob的动画曲线

    def getCurves( knob, views):
        curves = []
        for v in views:
            curves.extend( knob.animations(v) )
        return curves

bakeCurve 烘焙动画曲线

    def bakeCurve( curve, first, last, inc):
        for f in xrange(first, last, inc):
            curve.setKey(f, curve.evaluate(f))
        curve.setExpression( 'curve')

有了上面两个函数就可以写bakeExpressionKnobs了，需要5个参数

    def bakeExpression( node, first, last, inc, views):
            expKnobs = [k for k in node.knobs().values() if k.hasExpression() ]

然后就可以运行getCurves了

    allCurves = []
    for k in expKnobs:
        allCurves += getCurves( k, views )

随后bake数据

    for c in allCurves:
        bakeCurve(c, first, last, inc)

完整的bakeExpressionKnobs()

    def bakeExpressionKnobs( node, first, last, inc, views ):
        expKnobs = [ k for k in node.knobs().values if k.hasExpression() ]
        allCurves = []
        for k in expKnobs:
            allCurves += getCurves(k, views )

        for c in allCurves:
            bakeCurve( c, first, last, inc)

所有代码：

import nuke
def bakeCurve( curve, first, last, inc ):
    '''bake an expresison curve into a keyframes curve'''
    for f in xrange( first, last, inc ):
        curve.setKey( f, curve.evaluate( f ) )
    curve.setExpression( 'curve' )

####################################################
def getCurves( knob, views ):
    '''return a list of all animation curves found in the given knob'''
    curves = []
    for v in views:
        curves.extend( knob.animations( v ) )
    return curves

####################################################
def bakeExpressionKnobs( node, first, last, inc, views ):
    '''bake all knobs in node that carry expressions'''
    # GET ALL KNOBS WITH EXPRESSIONS IN THEM
    expKnobs = [ k for k in node.knobs().values() if k.hasExpression() ]

    # GET ALL CURVES INSIDE THAT KNOB INCLUDING SPLIT FIELDS AND VIEWS
    allCurves = []
    for k in expKnobs:
        allCurves += getCurves( k, views )

    # BAKE ALL CURVES
    for c in allCurves:
        bakeCurve( c, first, last, inc )

####################################################
def bakeDependentNodes():
    '''Add this to onUserDestroy callback - not yet implemented'''
    parentNode = nuke.thisNode() # THIS IS GIVEN TO US BY THE CALLBACK, i.e. WHEN A NODE IS DELETED - WELL, NOT YET
    depNodes  = parentNode.dependent( nuke.EXPRESSIONS )

    ret = nuke.getFramesAndViews( 'bake curves in dependent nodes?', '%s-%s' % (parentNode.firstFrame(), parentNode.lastFrame()) )
    if not ret:
        return
    fRange = nuke.FrameRange( ret[0] )
    views = ret[1]

    for n in depNodes:
        bakeExpressionKnobs( n, fRange.first(), fRange.last(), fRange.increment(), views )


####################################################
def bakeSelectedNodes():
    '''bake selected nodes' knobs that carry expressions'''
    ret = nuke.getFramesAndViews( 'bake curves in selected nodes?', '%s-%s' % (nuke.root().firstFrame(), nuke.root().lastFrame()) )
    if not ret:
        return
    fRange = nuke.FrameRange( ret[0] )
    views = ret[1]

    for n in nuke.selectedNodes():
        bakeExpressionKnobs( n, fRange.first(), fRange.last(), fRange.increment(), views )

选择节点并执行：

bakeSelectedNodes()