## PyGeom at FreeGeek: Rita's Notes

```Hello All,

This week Kirby talked about another piece of software we will be using soon to draw with!!!

You will need to go to www.povray.org  and download povray version 3.5.  But while you are
there, look at those amazing pictures that were made with this software!  POVray will allow
us to draw just about anything it seems, undoubtedly with a bit (some...a lot) of practice.
POVray will let us define where an eye (or camera) is and where light sources are, and then
bounce light off of whatever object we've given it , such as a triangle, cube, etc.  POVray will
create the image that the eye would see, based on the info we supplied about the object's
shape, texture, color, etc.

Don't let this overwhelm you, we will start slow.  Basically we are going to use Python to put
together lists of points, and then connect them.  We will send this info from Python to POVray
and let it draw what we created.

Go to www.povray.org.  In the yellow bar at the top click "download".  On the next page,
will step you through.  (You'll want to save it to disk...)

This week we talked about Python's data structures.  These structures in some form or
another show up in just about all programming languages.  They are:

Lists:  Lists in Python can be recognized by the square brackets with elements inside,
separated by comas.  We can retrieve things from a list using an index #.
Ex:  [ 'a', 1, 5]

Dictionary;  Dictionaries can be recognized by their 'curly' brackets.  We can retrieve
things from a dictionary using names.
Ex: {    }

Tuples:  A tuple is like a list but uses parenthesis, with elements inside.  A tuple cannot
be changed once it's defined.  For example you could not change the order of the
elements in a tuple.
Ex: (   )

String:  A sequence of characters.
Ex: 'kirby'

We learned that objects, such as those in a list have attributes  and methods.  Attributes
are characteristics and methods are actions. For example, a dog might have the attributes
of being hairy or angry.  A dog's methods might be barking or eating.

Kirby went on to expose us to the syntax using an object with it's attributes or methods.

Ex;  object. attribute    could be stated   mydog.texture =  'brown, furry'
Ex.  object.method      could be stated   mydog.bark(3), where 3 refers to the loudness of the bark

Here's a few other examples we played with,

>>>a = 'kirby'
>>>a.upper ( ), will return KIRBY

>>>a = 'the great escape'
>>>a.title( ), will return The Great Escape

We can ask for a directory of all the 'methods' (that is, things) Python can do with a string (or
list, dictionary or tuple), by doing the following:

>>>dir(a)
where a is the name of a string

See ya Friday!

Rita Petherbridge
rbridge@ix.netcom.com

Kirby can be reached at:  kirby@4dsolutions.net.
```

Oregon Curriculum Network