How can I animate a 3d object in numpy - python

I have the following code :
import numpy as np
import matplotlib.pyplot as plt
import mpl_toolkits.mplot3d.axes3d as p3
from matplotlib import animation
fig = plt.figure()
p3.autoscale = True
ax = p3.Axes3D(fig)
ax.grid(True)
ax.set_xlim(-100, 100)
ax.set_ylim(-100, 100)
ax.set_zlim(-100, 100)
u = np.r_[0:2*np.pi:100j]
v = np.r_[0:np.pi:100j]
scale = 15
x = scale * np.outer(np.cos(u),np.sin(v))
y = scale * np.outer(np.sin(u),np.sin(v))
z = scale * np.outer(np.ones(np.size(u)),np.cos(v))
Line3DCollection_1 = ax.plot_wireframe(x,y,z, rstride=50, cstride=50)
Line3DCollection_2 = ax.plot_wireframe(x + 50,y,z, rstride=50, cstride=50)
# initialization function: plot the background of each frame
def init():
return Line3DCollection_1,
def animate(i):
print("frame :" + str(i))
x = 50 * np.sin(np.radians(i))
y = 50 * np.cos(np.radians(i))
path = plt.plot([x],[y],[0], 'bo')
return path
# call the animator. blit=True means only re-draw the parts that have changed.
anim = animation.FuncAnimation(fig, animate, init_func=init, frames=360, interval=0.1, blit=True)
plt.show()
This will produce 2 spheres and a path that I want one of the spheres to take, but I'm not sure how to include this in the animation, I can animate the path, but not the 'Line3DCollection_2' sphere.
Does anyone have any ideas?
Thanks.

Related

Python function animation for two graphes (displayed after each other)

I have two data sets y1 = vol1 and y2 = vol2 for the same x range (0 to 5000 in steps of 10). I would like to use function animation in order to first animate y1 and after that animate y2 while the graph of y1 remains.
This is what I got from combing several examples (incl. this):
import numpy as np
from matplotlib import pyplot as plt
from matplotlib.animation import FuncAnimation
x = range(0, 5000, 10)
y1 = vol1
y2 = vol2
fig, ax = plt.subplots()
ax.set_xlim(0, 5000)
ax.set_ylim(0, 1000)
l1, = plt.plot([],[],'b-')
l2, = plt.plot([],[],'r-')
def init1():
return l1,
def init2():
return l2,
def animate1(i):
l1.set_data(x[:i],y1[:i])
return l1,
def animate2(i):
l2.set_data(x[:i-500],y2[:i-500])
return l2,
def gen1():
i = 0
while(i<500):
yield i
i += 1
def gen2():
j = 500
while(j<1000):
yield j
j += 1
ani1 = FuncAnimation(fig, animate1, gen1, interval=1, save_count=len(x),
init_func=init1, blit=True,
repeat=False)
ani2 = FuncAnimation(fig, animate2, gen2, interval=1, save_count=len(x),
init_func=init2, blit=True,
repeat=False)
# ani.save('ani.mp4')
plt.show()
My idea was to make two 'counters' gen1 andgen2 but since I have the same x values for both data sets, I tried to compensate that in the animate2 function. But this doesn't work..
Obviously, I'm quite new to python and I appreciate any help.
I would do just one animation, keeping track of the frame with respect to the line length:
import numpy as np
from matplotlib import pyplot as plt
from matplotlib.animation import FuncAnimation, FFMpegWriter
x = np.linspace(0, 2 * np.pi)
y1 = np.sin(x)
y2 = np.cos(x)
k = 0
fig, ax = plt.subplots()
ax.set_xlim(0, x.max())
ax.set_ylim(-1.5, 1.5)
l1, = plt.plot([],[],'b-')
l2, = plt.plot([],[],'r-')
def animate1(i):
global k
if k > 2 * len(x):
# reset if "repeat=True"
k = 0
if k <= len(x):
l1.set_data(x[:k],y1[:k])
else:
l2.set_data(x[:k - len(x)],y2[:k - len(x)])
k += 1
ani1 = FuncAnimation(fig, animate1, frames=2*len(x), interval=1, repeat=True)
writer = FFMpegWriter(fps=10)
ani1.save("test.mp4", writer=writer)
plt.show()

How do I animate the following lines in matplotlib using my `ndarray`?

I have the following function to generate a brownian motion:
from matplotlib import pyplot as plt
from matplotlib import animation
import numpy as np
from scipy.stats import uniform, norm
def walk(n):
angle = uniform.rvs( size=(n,), loc=.0, scale=2.*np.pi )
r = norm.rvs( size=n )
x = np.cumsum( r * np.cos(angle) )
y = np.cumsum( r * np.sin(angle) )
return np.array((x, y, r, angle))
If I call this like brownian = walk(1000), and plot it like ax.plot( brownian[0,:], brownian[1,:], color='k'), it plots it correctly, but now I want to animate it and do this (taken from here):
# Length of array (or how long motion is modeled)
motionLength = 1000
# First set up the figure, the axis, and the plot element we want to animate
fig = plt.figure()
xyMin = brownian.min() * 1.2
xyMax = brownian.max() * 1.2
plt.axis('equal')
ax = plt.axes(xlim=(xyMin,xyMax), ylim=(xyMin,xyMax))
line, = plt.plot([], [], lw=1, color='k')
# initialization function: plot the background of each frame
def init():
line.set_data([], [])
return line,
def iterr(i):
line.set_data(brownian[:i,0],brownian[[:i,1]) # problem here?
return line,
anim = animation.FuncAnimation(fig, iterr, init_func=init, frames=motionLength,
interval=100, blit=True)
anim.save('test_animation_2.mp4', fps=120, bitrate=-1,
extra_args=['-vcodec', 'libx264'])
But I cannot seem to get it to work. I guess the problem lies in my building the lists in iterr, because either 1) I'm not taking the correct values with my slices, or 2) I'm not getting getting from walk what I think I'm getting.
How do I rewrite iterr to work with my ndarray.

Animate Points Movement in Scatter plot (matplotlib python)

I'm not a beginner, but I'm also not advanced dev of python code.
I'm been trying to animate points movement in scatter plot and to put annotation on every point. All I have done is animation of one point with no annotation. I've searched similar solutions, but it's so confusing. Any help is welcome. This is what I've done.
from mpl_toolkits.mplot3d import axes3d
import matplotlib.pyplot as plt
import matplotlib.animation as animation
frame_count = 0
points = reading_file("some_data") # this method is not of intrest
def make_one_point(i):
global frame_count, points
ex = [1]
ey = [1]
ez = [1]
point = points[i]
frame = point[frame_count]
ex[0] = frame[0]
ey[0] = frame[1]
ez[0] = frame[2]
frame_count += 1
return ex, ey, ez
def update(i):
global frame_count, points
if frame_count < len(points[i]):
return make_one_point(i)
else:
frame_count = 0
return make_one_point(i)
fig = plt.figure()
ax1 = fig.add_subplot(111, projection='3d')
ax1.set_xlim3d(-500, 2000)
ax1.set_ylim3d(-500, 2000)
ax1.set_zlim3d(0, 2000)
x = [1]
y = [1]
z = [1]
scat = ax1.scatter(x,y,z)
def animate(i):
scat._offsets3d = update(0)
ani = animation.FuncAnimation(fig, animate,
frames=len(points[10]),
interval=100, repeat=True)
plt.show()
How to animate more points at the same time, and put annontation on every one of them? There are 50 points, and I'm not so consern about efficiency, just to make it work.
This code output is moving one point animation
It turns out animating Text in 3D was harder than I anticipated. Not surprisingly, I was able to find the solution to the problem in an answer from #ImportanceOfBeingErnest. I then simply adapted the code I had already written in a previous answer, and produced the following code:
import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D, proj3d
import matplotlib.animation as animation
N_points = 10
def update(num, my_ax):
# the following corresponds to whatever logic must append in your code
# to get the new coordinates of your points
# in this case, we're going to move each point by a quantity (dx,dy,dz)
dx, dy, dz = np.random.normal(size=(3,N_points), loc=0, scale=1)
debug_text.set_text("{:d}".format(num)) # for debugging
x,y,z = graph._offsets3d
new_x, new_y, new_z = (x+dx, y+dy, z+dz)
graph._offsets3d = (new_x, new_y, new_z)
for t, new_x_i, new_y_i, new_z_i in zip(annots, new_x, new_y, new_z):
# animating Text in 3D proved to be tricky. Tip of the hat to #ImportanceOfBeingErnest
# for this answer https://stackoverflow.com/a/51579878/1356000
x_, y_, _ = proj3d.proj_transform(new_x_i, new_y_i, new_z_i, my_ax.get_proj())
t.set_position((x_,y_))
return [graph,debug_text]+annots
# create N_points initial points
x,y,z = np.random.normal(size=(3,N_points), loc=0, scale=10)
fig = plt.figure(figsize=(5, 5))
ax = fig.add_subplot(111, projection="3d")
graph = ax.scatter(x, y, z, color='orange')
debug_text = fig.text(0, 1, "TEXT", va='top') # for debugging
annots = [ax.text2D(0,0,"POINT") for _ in range(N_points)]
# Creating the Animation object
ani = animation.FuncAnimation(fig, update, fargs=[ax], frames=100, interval=50, blit=True)
plt.show()

Animate a collection of patches in matplotlib

I'm trying to animate a set of particles that follow trajectories in x, y and z. Each object has a specific radius which is relevant in axis units, which is why I want each object to be represented by a Circle patch, where I can specify the size of the patch (as opposed to a scatter plot, where I have to convert the size to axis units).
The other constraint is that I want the patches to be colored according to a colormap, with the color of the patch determined by the value of z.
The only way I have found of plotting a set of patches with a colormap is by putting them inside a collection. So, this successfully produces one frame
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as anm
import matplotlib.collections as clt
fig, ax = plt.subplots(1,1,figsize=(7,7))
ax.set_xlim(-1,1)
ax.set_ylim(-1,1)
n_of_particles = 3
frames = 10
radius = 0.05
x = 0.5*np.random.randn(frames,n_of_particles)
y = 0.5*np.random.randn(frames,n_of_particles)
z = 0.5*np.random.randn(frames,n_of_particles)
patches = []
for p in range(n_of_particles):
circle = plt.Circle((x[0,p], y[0,p]), radius)
patches.append(circle)
collection = clt.PatchCollection(patches, cmap=plt.cm.jet, alpha=0.4)
collection.set_array(z[0,:])
collection.set_clim([-1, 1])
plt.colorbar(collection)
ax.add_collection(collection)
But how do I animate it?
I have tried to add at the end (instead of ax.add_collection(collection))
def animate(frame):
patches = []
for p in range(n_of_particles):
circle = plt.Circle((x[frame,p], y[frame,p]), radius)
patches.append(circle)
collection = clt.PatchCollection(patches, cmap=plt.cm.jet, alpha=0.4)
collection.set_array(z[0,:])
ax.add_collection(collection)
return collection,
and then:
anim = anm.FuncAnimation(fig, animate,
frames=10, interval=100, blit=True)
HTML(anim.to_html5_video())
But it doesn't erase the previous frame.
Ideally, I would prefer to change the position of the patches, instead of redefining them. But I don't know how to modify a collection.
Any ideas?
The idea would of course be to add the collection only once to the axes. Then change the artists inside the collection via collection.set_paths.
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as anm
import matplotlib.collections as clt
fig, ax = plt.subplots(1,1,figsize=(7,7))
ax.set_xlim(-1,1)
ax.set_ylim(-1,1)
n_of_particles = 3
frames = 10
radius = 0.05
x = 0.5*np.random.randn(frames,n_of_particles)
y = 0.5*np.random.randn(frames,n_of_particles)
z = 0.5*np.random.randn(frames,n_of_particles)
patches = []
for p in range(n_of_particles):
circle = plt.Circle((x[0,p], y[0,p]), radius)
patches.append(circle)
collection = clt.PatchCollection(patches, cmap=plt.cm.jet, alpha=0.4)
collection.set_array(z[0,:])
collection.set_clim([-1, 1])
fig.colorbar(collection)
ax.add_collection(collection)
def animate(frame):
patches = []
for p in range(n_of_particles):
circle = plt.Circle((x[frame,p], y[frame,p]), radius)
patches.append(circle)
collection.set_paths(patches)
collection.set_array(z[frame,:])
anim = anm.FuncAnimation(fig, animate,
frames=10, interval=1000, blit=False)
plt.show()
The other option could be to use the solution provided in this answer: matplotlib change a Patch in PatchCollection
and create an UpdatablePatchCollection. This would allow to just update the properties of the original patches inside the loop.
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as anm
import matplotlib.collections as clt
fig, ax = plt.subplots(1,1,figsize=(7,7))
ax.set_xlim(-1,1)
ax.set_ylim(-1,1)
n_of_particles = 3
frames = 10
radius = 0.05
x = 0.5*np.random.randn(frames,n_of_particles)
y = 0.5*np.random.randn(frames,n_of_particles)
z = 0.5*np.random.randn(frames,n_of_particles)
patches = []
for p in range(n_of_particles):
circle = plt.Circle((x[0,p], y[0,p]), radius)
patches.append(circle)
class UpdatablePatchCollection(clt.PatchCollection):
def __init__(self, patches, *args, **kwargs):
self.patches = patches
clt.PatchCollection.__init__(self, patches, *args, **kwargs)
def get_paths(self):
self.set_paths(self.patches)
return self._paths
collection = UpdatablePatchCollection(patches, cmap=plt.cm.jet, alpha=0.4)
collection.set_array(z[0,:])
collection.set_clim([-1, 1])
fig.colorbar(collection)
ax.add_collection(collection)
def animate(frame):
for p in range(n_of_particles):
patches[p].center = x[frame,p], y[frame,p]
collection.set_array(z[frame,:])
anim = anm.FuncAnimation(fig, animate,
frames=10, interval=1000, blit=False)
plt.show()

Animate a segment in a 3d space

I got a .dat file which contains the coordinates of a segment in 3d space.
The file has several lines, each single line characterizes the position at a particular time.
I tried this code:
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
from mpl_toolkits.mplot3d import Axes3D
dati = np.loadtxt('dati.dat')
t=0
p1=[dati[t,1],dati[t,2],dati[t,3]]
p2=[dati[t,4],dati[t,5],dati[t,6]]
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
seg,=ax.plot(p1,p2)
def updateFigure(t,dati,seg):
p1=[dati[t,1],dati[t,2],dati[t,3]]
p2=[dati[t,4],dati[t,5],dati[t,6]]
seg.set_data(p1,p2)
return seg,
ani=animation.FuncAnimation(fig, updateFigure,iMax, fargs=(dati,seg), interval=100, blit=True)
plt.show()
The program doesn't report errors but the figure doesn't move.
The same code, a bit modified, in the 2d space works..
Instead of calling set_data, you could set seg._verts3d directly, though note that manipulating the private variable _verts3d is relying on an implementation detail, not part of the Line3D public interface:
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
from mpl_toolkits.mplot3d import Axes3D
iMax = N = 500
theta = np.linspace(0, 6*np.pi, N)
x = np.cos(theta)
y = np.sin(theta)
z = np.linspace(0, 1, N)
step = 10
dati = np.column_stack(
[theta, x, np.roll(x, -step), np.roll(x, -2*step)
, y, np.roll(y, -step), np.roll(y, -2*step)
, z, np.roll(z, -step), np.roll(z, -2*step)])
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
seg, = plt.plot([], [])
ax.set_xlim3d(-1, 1)
ax.set_ylim3d(-1, 1)
ax.set_zlim3d(0, 1)
def init():
return seg,
def updateFigure(t):
p1 = dati[t, 1:4]
p2 = dati[t, 4:7]
p3 = dati[t, 7:10]
seg._verts3d = (p1, p2, p3)
return seg,
ani = animation.FuncAnimation(
fig, updateFigure
, init_func=init
, frames=iMax
, interval=5, blit=True)
plt.show()

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