Maya Python Studying

Tuesday, February 26, 2013

Data Attributes

While data attributes defined both ways may have unique values for any particular instance, those that exist in the class definition can be accessed without an instance of the class, as the following hypothetical example:
import sys;
class NewClass():
data_attribute1 = 1;
def __init__(self):
self.data_attribute2 = 2;
print(NewClass.data_attribute1);
try:
print(NewClass.data_attribute2);
except AttributeError:
print(sys.exc_info()[0]);
instance = NewClass();
print(instance.data_attribute1);
print(instance.data_attribute2);
1
<type 'exceptions.AttributeError'>
1
2

Sunday, February 24, 2013

Basics of class implementation in Python

By reading ten pages of Chapter five today, I learnt instantiation and attributes. Here is what I programmed during reading the book:

class NewClass:
pass;
dir(NewClass);
# Result: ['__doc__', '__module__'] #
class NewClass(object):
pass;

dir(NewClass);
# Result: ['__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__'] #
instance1 = NewClass();
instance2 = NewClass();
instance3 = NewClass();
class NewClass():
data_attribute = None;
def function_attribute(*args):pass;
print(dir(NewClass));
['__doc__', '__module__', 'data_attribute', 'function_attribute']

Friday, February 22, 2013

Object-oriented programming

So today, I plan to start learning chapter 5. But before that, I need to review what is object-oriented programming, and some basic concepts.

1) Object-oriented programming (OOP) is a programming paradigm that represents concepts as "objects" that have data fields (attributes that describe the object) and associated procedures known asmethods. Objects, which are usually instances of classes, are used to interact with one another to design applications and computer programs.

2) Class is a construct that is used to create instances of itself – referred to as class instances, class objects, instance objects or simply objects. A class defines constituent members which enable its instances to have state and behavior.

3) Object is a location in memory having a value and referenced by an identifier. An object can be a variable, function, or data structure. With the later introduction of object-oriented programming the same word, "object," refers to a particular instance of a class.

4）Method is a subroutine (or procedure) associated with a class. Methods define the behavior to be exhibited by instances of the associated class at program run time. Methods have the special property that at run-time they have access to data stored in an instance of the class (or class instance or class object or object) they are associated with and are thereby able to control the state of the instance.

5）Instance is an occurrence or a copy of an object, whether currently executing or not. Instances of a class share the same set of attributes, yet will typically differ in what those attributes contain.

I also learnt the three main differences between object-oriented and process-oriented. They are Inheritance, Encapsulation,Polymorphism. Since they are so complicated, it is better not describe them in detail here.

Wednesday, February 20, 2013

Using Eclipse as a Maya IDE

I used two hours to setup Eclipse as a Maya IDE. But until now, it doesn't work.
Here is the link I tried:
http://www.creativecrash.com/tutorials/using-eclipse-as-a-maya-ide#tabs
http://nealbuerger.com/2012/07/eclipse-python-editor-maya-2013/
http://autodesk.com/us/maya/2011help/PyMel/eclipse.html

I'm too tired now, but I will finish this tomorrow. Hope I could make it work tomorrow!!!

Tuesday, February 19, 2013

My first Module: spike

My first module is pretty simple, just create a soccer ball and then extrude it twice as the picture shows below. But I did learn lots of new maya commands and understand Module deeper. Here is the script:

"""This script prints some information and creates a spike ball."""
import maya.cmds
def addSpikes(obj):
"""This function adds spikes to a polygon object."""
try: polycount = maya.cmds.polyEvaluate(obj, face=True)
except: raise
for i in range(0, polycount):
face = '%s.f[%s]'%(obj, i)//遍历obj的所有face
maya.cmds.polyExtrudeFacet(face, ltz=1, ch=0)//第一次extrude
maya.cmds.polyExtrudeFacet(face, ltz=1, ch=0, ls=[.1,.1,.1])//第二次extrude 缩小为上一次的0.1倍
maya.cmds.polySoftEdge(obj, a=180, ch=0)
maya.cmds.select(obj)

print('module name: %s'%__name__)
print('globals:')
for k in globals().keys(): print('\t%s'%k)
addSpikes(maya.cmds.polyPrimitive(ch=0)[0])//创建一个soccer ball
Result：

Monday, February 18, 2013

Commands Python Help

1) Useful to check out the flags of each maya command
import maya.cmds;
print(maya.cmds.help('maya command'));

2) Good website to check out detail information about each maya command

http://download.autodesk.com/us/maya/2011help/CommandsPython/

Sunday, February 17, 2013

50 Important Modules in Python

This week I learnt a lot about Module in Python even I do not post my study notes on this blog anymore.Module, in my understanding, is a standalone Python file containing a sequence of definitions and executable statements and Python itself ships with a large library of default modules.

Here, I summarized 50 really useful Modules including Databases, GUIs, Images, Sound, OS interaction, Web, etc.

Graphical interface wxPython http://wxpython.org

Graphical interface pyGtk http://www.pygtk.org

Graphical interface pyQT http://www.riverbankcomputing.co.uk/pyqt/

Graphical interface Pmw http://pmw.sourceforge.net/

Graphical interface Tkinter 3000 http://effbot.org/zone/wck.htm

Graphical interface Tix http://tix.sourceforge.net

Database MySQLdb http://sourceforge.net/projects/mysql-python/

Database PyGreSQL http://www.pygresql.org/

Database Gadfly http://gadfly.sourceforge.net/

Database SQLAlchemy http://www.sqlalchemy.org/

Database psycopg http://www.initd.org/pub/software/psycopg/

Database kinterbasdb http://kinterbasdb.sourceforge.net/