Maya Python/PyQt Alignment Plugin Rewritten and Extended

Unfortunately, a few days ago my computer decided to crash forcing me to reinstall the OS. I thought i had all my code files and stuff safe in the Data drive... well I proved to trust wrong because guess where the system got installed with the recovery partition? yes !! in my data drive!!. What pisses me off mostly is that i ve lost all the five programming assignments from the Coursera MOOC "Algorithms, part I", which i ve previously talked about in this blog. Other code I had was some python/pygame computational geometry stuff i did in my spare time.

And finally, my first Maya plugin also was lost. So far from being discouraged, i decided to recode again the plugin adding the feature someone suggested me in the spanish TD facebook group and also i decided to extend the plugin in order to be able to do 3 types of operations with the object's pivot.

Before i post the youtube video showing how it works i will talk a bit about some tips i didn't post previously that i had forgot and that i had to face again.

Qt Designer

I used Qt Designer to visually establish the layout of my window. Two things about this:

- first, i wanted to use two sets of exclusive radioButtons which led me to set two separate QButtonGroups. With the left button on each QButtonGroup i selected the radiobuttons to be members of it.

- Secondly. I wanted to put QGroupBoxes because it is a feature that enhances the visual look of the window as well as helping figure out visually which parameters are part of the same option. For this you have to firstly select the groupbox and drop it in the window layout, and after and only after, put inside the necessary widgets. You will notice if you have done it correctly because the widgets appear to be "parented" to the groupbox in the "Object Inspector" 

This is how it looks like:

UI xml file conversion to python file

The .ui file saved by Qt Designer is no more than an xml file that has to be converted to .py file with all the window layout so that we can instance it in our window class from our Python/PyQt main file.

For this we open the windows command line, we set the path to our .ui file and type:

pyuic4 align.ui > align.py

Our Maya Plugin

We declare our class that this time inherits from QWidget and add the WindowStayOnTopHint.

class AlignWindow(QtGui.QWidget):
    def __init__(self, parent=None):

        QtGui.QWidget.__init__(self, parent, QtCore.Qt.WindowStaysOnTopHint)
        self.ui = Ui_Alignment()
        self.ui.setupUi(self)

Since Maya is running its own QApplication thread this code causes Maya to stall:

if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    mw = AlignWindow()
    mw.show()
    sys.exit(app.exec_())

But instead can make the window visible when running from Visual Studio. To make it work in Maya it suffices to write:

myWindow = AlignWindow()
myWindow.show()

Three different Pivot Alignment Techniques

- pivot in object(s). Aligns the pivot(s) within the bounding box(es) of each of the object(s). That was what my first plugin, yes the one i lost did.

- pivot(s) to object's pivot. Aligns a set of object(s) pivot(s) to the last selected object's pivot.

- object(s) to object. Aligns a set of object(s)'s pivot(s) to the last object selected but this time so that we translate the objects maintaining their relative position regarding their pivots.