Problem

While using line plots, the alpha attribute is unable to use the transparency for visualizing the density of lines along the line of sight.
Consider the following sample code:

import numpy as np
import matplotlib.pyplot as plt

ax = plt.axes(projection='3d')
x = np.arange(0, np.pi*20, .1)
ax.plot(np.sin(x), np.cos(x), x, c=[.8, .8, .8], linewidth=4, alpha=.5)
plt.show()

Which currently gives this:

Whereas on MATLAB, we get this (notice the additive blending of colors in intersections):

Proposed solution

Maybe add additive blending in the same group.