Astrid Astrid - 2 months ago 12
Python Question

Colouring in between two lines in 3D plot

I am trying the fill the space between my lines in 3D.

I have the following code:

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

class plotting3D(object):
"""
Class to plot 3d
"""

def __init__(self):
pass

def cc(self, arg):
return colorConverter.to_rgba(arg, alpha=0.6)

def poly3d(self, df):
"""
Method to create depth of joints plot for GP regression.
"""
fig = plt.figure(figsize=(10,10))
ax = fig.gca(projection='3d')

which_joints = df.columns
dix = df.index.values
zs = [1,4]
verts = []
for j in which_joints:
verts.append(list(zip(dix,df[j])))

poly = PolyCollection(verts,facecolors=[self.cc('r'), self.cc('g')])
poly.set_alpha(0.6)
ax.add_collection3d(poly, zs=zs, zdir='y')

ax.set_ylim([0, 5])
ax.set_zlim([0, 20])
ax.set_xlim([0,dix[-1]])
ax.grid(False)
ax.set_xlabel('X')
ax.set_ylabel('Y')
ax.set_zlabel('Z')

plt.show()


Some synthetic data:

k= pd.DataFrame(20*np.random.rand(10,2),columns=['foot','other_foot'])


Produces this:

enter image description here

Now I want to fill the space between the lines and say
z=-30
NOT
z=0
which is what I am trying to change.

df.index.values
take a values between
0
and say
1000
. And the
ang
dataframe has values ranging from
-30
to
10
.

Hence, I am trying to produce an offset version of this:

enter image description here

Answer

Another solution to my suggestion in the comments is to use fill_between; there you have the possibility to set the lower boundary. fill_between returns a PolyCollection, so you can add it to the 3d figure similar to what you are doing now:

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

fig = plt.figure(figsize=(10,10))
ax = fig.gca(projection='3d')

# +/- your data:
z = [0,10,10,-20,10,0]
x = [0,1000,1500,2500,3000,3500]

ax.add_collection3d(plt.fill_between(x,z,0),   zs=1, zdir='y') # lower boundary z=0
ax.add_collection3d(plt.fill_between(x,z,-30), zs=5, zdir='y') # lower boundary z=-30

ax.set_ylim([0, 5])
ax.set_zlim([-30, 20])
ax.set_xlim([0,3500])

enter image description here