Maya Python：cmds.button() 传递UI变量并调用函数？

Question

首先，这里似乎是一个很好的地方，可以学习更多关于编程的知识。
我写了一个Maya的Python脚本，里面有两个功能都能正常工作，但我在让UI按钮调用superExtrude()这个函数时遇到了麻烦。
第一个功能负责处理几何网格的操作，第二个功能应该是为用户输入提供界面：

import maya.cmds as cmds

def superExtrude(extrScale, extrDist):
    """Loops through a list of selected meshes and extrudes all of the mesh faces to produce a polygon frame, based on existing mesh tesselations"""
    myObjectLt = cmds.ls(selection=True)

    for i in range(len(myObjectLt)):
        numFaces = cmds.polyEvaluate(face=True)
        item = myObjectLt[i] + ".f[:]"
        cmds.select(clear=True)
        cmds.select(item, replace=True)

        #extrude by scale
        cmds.polyExtrudeFacet(constructionHistory=True, keepFacesTogether=False, localScaleX=extrScale, localScaleY=extrScale, localScaleZ=extrScale)
        selFaces = cmds.ls(selection=True)
        cmds.delete(selFaces)

        #extrude by height
        cmds.select(item, replace=True)
        cmds.polyExtrudeFacet(constructionHistory=True, keepFacesTogether=True, localTranslateZ=extrDist)

def extrWindow():
    """Creates the user interface UI for the user input of the extrusion scale and height"""
    windowID = "superExtrWindow"

    if cmds.window(windowID, exists=True):
        cmds.deleteUI(windowID)

    cmds.window(windowID, title="SuperExtrude", sizeable=False, resizeToFitChildren=True)
    cmds.rowColumnLayout(numberOfColumns=2, columnWidth=[(1,120),(2,120)], columnOffset=[1,"right",3])

    cmds.text(label="Extrusion Scale:")
    extrScaleVal = cmds.floatField(text=0.9)
    cmds.text(label="Extrusion Height:")
    extrDistVal = cmds.floatField(text=-0.3)
    cmds.separator(height=10, style="none")
    cmds.separator(height=10, style="none")
    cmds.separator(height=10, style="none")

    cmds.button(label="Apply", command=superExtrude(extrScaleVal, extrDistVal))
    cmds.showWindow()

extrWindow()

我对Python和Maya脚本还很陌生，所以任何帮助都会非常感激。:)

Answer 1

我把所有东西都换成了pymel，你应该学习这个。cmds真是糟糕透了。花点时间看看你和我之间的区别。像这样的脚本能帮助你入门。如果需要进一步的解释，随时告诉我。

为了你的学习，建议你去学pymel。

pymel的在线文档在这里 = http://download.autodesk.com/global/docs/maya2014/en_us/PyMel/

import pymel.core as pm
def superExtrude(*args):
    """Loops through a list of selected meshes and extrudes all of the mesh faces to produce a polygon frame, based on existing mesh tesselations"""
    #pymel uses python classes to make things easier
    #its ok to not understand what a class is but just think of it the same as if you were to add an attribute to a polycube. 
    #your code variable now has attributes 

    #so with that pymel ls returns a list of PyNodes that correspond to the objects
    #cmds ls returns a list of strings which is very unuseful
    #if you look at the help docs you can find most of whats available
    myObjectLt = pm.ls(selection=True)


    for i in myObjectLt:
        #instead of cycling through by a number were gonna cycle through the list itself
        #i is now the item in the list

        #its unnecessary to select the objects because we can specify it in the polyExtrude
        #cmds.select(item,  replace=True)

        #the extrude commands selects things but im not sure what your trying to achive here by seperating
        #the scale extrude and translate extrude
        pm.select(cl=True)



        #the way poly objects wrok is that you have a transform node and a shape node
        # if you graph it in the hypershade you'll see the two nodes
        #the faces are part of the shape node i like accessing things by this node but just know you can do it like this
        #i.f  <-- f is your attribute and i is the item
        #using i.getShape() returns the shape node

        # http://download.autodesk.com/global/docs/maya2014/en_us/PyMel/generated/classes/pymel.core.uitypes/pymel.core.uitypes.FloatField.html?highlight=floatfield#pymel.core.uitypes.FloatField
        #since were using pymel the extrScaleVal has function that lets you get the value
        thisScale = extrScaleVal.getValue()


        pm.polyExtrudeFacet(i.getShape().f, constructionHistory=True, keepFacesTogether=False, localScaleX=thisScale, localScaleY=thisScale, localScaleZ=thisScale)
        #selFaces = cmds.ls(selection=True)
        pm.delete()

        #same as before
        thisDist = extrDistVal.getValue()
        #extrude by height
        pm.polyExtrudeFacet(i.getShape().f, constructionHistory=True, keepFacesTogether=True, localTranslateZ=thisDist)

def extrWindow():
    #global is a way to transfer variables from function to function the way you had it
    # you would have had to query the value from your parameters in superExtrude
    #instead do this
    global extrScaleVal, extrDistVal
    #which will makes these parameters to the other function


    """Creates the user interface UI for the user input of the extrusion scale and height"""
    windowID = "superExtrWindow"

    #instead of having a query run just use try except
    #which will just go to except when the try fails
    try:
        pm.deleteUI(windowID)
    except:
        pass

    pm.window(windowID, title="SuperExtrude", sizeable=False, resizeToFitChildren=True)
    pm.rowColumnLayout(numberOfColumns=2, columnWidth=[(1,120),(2,120)], columnOffset=[1,"right",3])

    pm.text(label="Extrusion Scale:")
    extrScaleVal = pm.floatField(v=0.9)
    pm.text(label="Extrusion Height:")
    extrDistVal = pm.floatField(v=-0.3)
    pm.separator(height=10, style="none")
    pm.separator(height=10, style="none")
    pm.separator(height=10, style="none")

    pm.button(label="Apply", c=superExtrude)
    pm.showWindow()

extrWindow()

Answer 2

St4rb0y

首先，你在第33和35行的floatField调用中使用了一个无效的标志，叫做'text'。你可能是想用'value'，所以把这两行改一下。

extrScaleVal = cmds.floatField(v=0.9)
extrDistVal = cmds.floatField(v=-0.3)

其次，在创建用户界面控件类型时，'command'标志需要一个字符串，所以你得把命令和它的参数用引号括起来：

cmds.button(label="Apply", command='superExtrude(extrScaleVal, extrDistVal)')

把那三行改了之后，应该就能正常工作了。

小贴士：

如果你想注释一行代码，可以用#，而不是把整行用三个单引号括起来。用三个引号更适合注释多行代码。

另一个关于控制命令标志的小技巧：你可以定义一个字符串变量来传递命令，然后用这个变量代替直接写字符串。这个技巧在创建动态控件时会很有用，比如根据用户的选择来组装命令：

comStr = "superExtrude(extrScaleVal, extrDistVal)"
cmds.button(label="Apply", command=comStr)

Answer 3

cmds.button(label="Apply", command=superExtrude(extrScaleVal, extrDistVal))

这一行代码调用了 superExtrude 并把它的返回值赋给了 command。因为 superExtrude 没有返回任何东西，所以这个按钮的命令实际上是 None。

也许你是想让 superExtrude 在按钮被点击时才被调用，这样的话你应该把它放在一个 lambda 函数里，这样就可以避免它被立即调用：

cmds.button(label="Apply", command=lambda *args: superExtrude(extrScaleVal, extrDistVal))

Answer 4

我不确定这是否是你想要的答案，但你需要了解关于Maya“命令”标志的一些事情：

• 如果你想在按钮的调用中放一个函数，你需要传入函数的名字，不要带任何参数（比如：command = myFunction），记得去掉最后的括号“()”。

• 在你的函数里，你需要加上“*args”，因为Maya的按钮总是会传递一个参数（我想是“False”）（例如：def myFunction(customArg1, customArg2, *args)）。

• 如果你想在按钮信号中传递参数，你需要使用functools模块里的部分函数（from functools import partial），用法是这样的： cmds.button(command = partial(myFunction, arg1, arg2, kwarg1=value1, kwarg2=value2)）。

还有一件事，关于pymel和cmds...这可能是个无止境的话题，但pymel并不是万能的... 当你需要处理大量信息（比如获取网格上的顶点列表）时，pymel的速度可能会比简单的Maya命令慢40倍。 它有优点也有缺点... 如果你刚开始学习Python，我不建议你现在就去接触pymel。 先熟悉语法和命令，当你掌握了之后，再转向pymel（在处理对象创建时非常有用）。

希望这些对你有帮助，

祝好

编辑：

根据你第一条帖子里的内容，你需要在代码中做的更改是：

import maya.cmds as cmds
from functools import partial

#You need to add the *args at the end of your function
def superExtrude(extrScaleField, extrDistField, *args):
    """Loops through a list of selected meshes and extrudes all of the mesh faces to produce a polygon frame, based on existing mesh tesselations"""
    myObjectLt = cmds.ls(selection=True)


    #In the function, we are passing the floatFields, not their values.
    #So if we want to query the value before running the script, we need to
    #use the floatField cmds with the "query" flag


    extrScale = cmds.floatField(extrScaleField, q=1, v=1)
    extrDist = cmds.floatField(extrDistField, q=1, v=1)

    for i in range(len(myObjectLt)):
        numFaces = cmds.polyEvaluate(face=True)
        item = myObjectLt[i] + ".f[:]"
        cmds.select(clear=True)
        cmds.select(item, replace=True)

        #extrude by scale
        cmds.polyExtrudeFacet(constructionHistory=True, keepFacesTogether=False, localScaleX=extrScale, localScaleY=extrScale, localScaleZ=extrScale)
        selFaces = cmds.ls(selection=True)
        cmds.delete(selFaces)

        #extrude by height
        cmds.select(item, replace=True)
        cmds.polyExtrudeFacet(constructionHistory=True, keepFacesTogether=True, localTranslateZ=extrDist)

def extrWindow():
    """Creates the user interface UI for the user input of the extrusion scale and height"""
    windowID = "superExtrWindow"

    if cmds.window(windowID, exists=True):
        cmds.deleteUI(windowID)

    cmds.window(windowID, title="SuperExtrude", sizeable=False, resizeToFitChildren=True)
    cmds.rowColumnLayout(numberOfColumns=2, columnWidth=[(1,120),(2,120)], columnOffset=[1,"right",3])

    cmds.text(label="Extrusion Scale:")

    # There were an error here, replace 'text' with 'value'
    # to give your floatField a default value on its creation

    extrScaleVal = cmds.floatField(value=0.9)
    cmds.text(label="Extrusion Height:")
    extrDistVal = cmds.floatField(value=-0.3)
    cmds.separator(height=10, style="none")
    cmds.separator(height=10, style="none")
    cmds.separator(height=10, style="none")

    # As said above, use the partial function to pass your arguments in the function
    # Here, the arguments are the floatFields names, so we can then query their value
    # everytime we will press the button.

    cmds.button(label="Apply", command=partial(superExtrude,extrScaleVal, extrDistVal))
    cmds.showWindow(windowID)

extrWindow()