n_particles_animation.py

# -*- coding: utf-8 -*-
"""
N PARTICLE ANIMATION

Creates N (line 46) frames for the animation from the file "results_R.txt". 
The number of colors (line 41) has to be the same as the number of bodies. 
The limits of the figure (line 36-38 and 63-65) should be changed for every different animation. 

To create the gif, it is recommended to use ffmpeg:
Terminal >>> ffmpeg -framerate 25 -i 'tmp%04d.png' -c:v libx264 -r 30 -pix_fmt yuv420p out.mp4
"""

import matplotlib as mpl
from mpl_toolkits.mplot3d import Axes3D
import numpy as np
import matplotlib.pyplot as plt

################################
#          LOADS DATA          #
################################

data=np.loadtxt("results_R.txt",unpack=True)

################################
#    SETS FIGURE PARAMETERS    #
################################
mpl.rcParams.update({'font.size': 6})
mpl.rcParams['legend.fontsize'] = 8
plt.ioff() #does not open all the figures
fig = plt.figure(figsize=(8,4.5))
ax1 = fig.gca(projection='3d')
ax1.set_xlabel('X axis')
ax1.set_ylabel('Y axis')
ax1.set_zlabel('Z axis')
ax1.cla()
ax1.set_xlim(-16, 16)
ax1.set_ylim(-6, 15)  
ax1.set_zlim(-0.7 , 0.7)

#The number of colors has to be the same as the number of bodies
colors = ["red", "orange", "blue", "green", "black", "purple", "yellow", "gray"] 

################################
#        CREATES FRAMES        #
################################
N = 500 #number of frames

counter = 0
scale = int(len(data[0])/N)

while counter < N:
    if counter <= 50:
        initial = 0
    else:
        initial = (counter - 50)*scale
        data[3*i], data[3*i+1], data[3*i+2]
    for i in range(len(colors)):
        ax1.scatter(data[3*i, counter*scale], data[3*i+1, counter*scale], data[3*i+2, counter*scale], color=colors[i])
    for i in range(len(colors)):
        ax1.plot(data[3*i, initial:counter*scale], data[3*i+1, initial:counter*scale], data[3*i+2, initial:counter*scale], color=colors[i])
    fig.savefig("tmp%04d.png" %(counter), format="png", dpi=240.) #6.4 4.8
    ax1.cla()
    ax1.set_xlim(-16, 16)
    ax1.set_ylim(-6, 15)  
    ax1.set_zlim(-0.7 , 0.7)
    counter += 1