Python Particles

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Introduction

This challenge will enable you to explore several basic concepts of python programming:
- use of lists
- use of loops
- use of mathematical expressions
- use of (logic) tests
- writing of files
The challenge will introduce you to two techniques by which particles can be procedurally created.

Technique 1: MEL Particles

This technique involves coding two python scripts. The first script (gen_coords.py) will generate positional data that will be used the second python script (mel_particles.py) to write a .mel file that will contain a MEL particle command. For example,

particle -p x y z -p x y z;

where x y z specify the positions of two particles. When the .mel file is sourced the particles will appear in the viewport.

The gen_coords.py script will implement at least 5 procedures. Each procedure will produce a list consisting of an arbitary number of x,y,z coordinates. An example implementaton is shown below.

#------------------------- gen_coords.py --------------------    
import random
import math
  
def cubic(num_coords, side):
    data = []
    count = 0
    half_side = side/2
    while count < num_coords:
        x = random.uniform(-half_side, half_side)
        y = random.uniform(-half_side, half_side)
        z = random.uniform(-half_side, half_side)
        data.append( (x,y,z) )
        count += 1    
    return data
#------------------------------------------------------------ 

You are expected to implement the following procedures,

    spherical(num_points, radius)
    cylindrical(num_points, radius, height)
    box(num_points, width, length, height)
    cone(num_points, radius, height)

An example implementation of the second python script (mel_particles.py) is shown next. Both the gen_coords.py and the mel_particles.py MUST be saved in your maya/scripts folder.

#---------------------- mel_particles.py --------------------
import gen_coords
  
def writeCubic(mel_path, num_particles, side):
    data = gen_coordss.cubic(num_particles, side)

    mel_out = open(mel_path, 'w')
    mel_out.write('particle\n')
    
    for x,y,z in data:
        mel_out.write('-p %1.3f %1.3f %1.3f\n' % (x,y,z))
        
    mel_out.write(';\n')
    mel_out.close()
#------------------------------------------------------------ 

The mel_particles.py script should implement the following procedures,

    writeSpherical(mel_path, num_points, radius)
    writeCylindrical(mel_path, num_points, radius, height)
    writeBox(mel_path, num_points, width, length, height)
    writeCone(mel_path, num_points, radius, height)

How the procedures implemented by your gen_coords.py and mel_particles.py scripts are used will be demonstrated during our zoom sessions.

Technique 2: Maya Particles

To successfully complete this part of the challenge you will write only one python script. For example, the next code snippet implements a procedure called cubicCloud().

#-------------------- maya_particles.py -----------------------
import maya.cmds as cmds
import gen_coords
  
def cubicCloud(num_particles, side):
    # Use the gen_coords module to create a list of points
    data = gen_coords.cubic(num_particles, side)
    
    # Use Maya's python command to add the cubic particle
    # cloud to the viewport. Capture and return the name of 
    # the particle system. 
    return cmds.particle(p=data)[0]
#------------------------------------------------------------    

You are expected to implement and add following procedures to the maya_particles script,

    sphericalCloud(num_points, radius)
    cylindricalCloud(num_points, radius, height)
    boxCloud(num_points, width, length, height)
    conicalCloud(num_points, radius, height)

How the procedures implemented by your maya_particles script are used in Maya will be demonstrated during our zoom sessions.

What is Expected?

The technical breakdown on your web page should show the following.
1     at least one rendered image of each of the Maya particle shapes,
2     a technical breakdown that explains how the images were created.

Grading

The following categories will be used for grading your work.