Color of contour lines on surface plot affected by axis range.

[peterjbrown519]

Hi,

It seems that if the zaxis range is not set to 'auto' then the colors of the contour lines will default to the color of the surface itself. Here is a short code snippet that reproduces the bug.

import plotly.plotly as py
import plotly.graph_objs as go
import numpy as np

# Bug where contour lines cannot be colored if they don't all appear on the plotted surface.

def f(x,y):
	return np.outer(x,y)

x = np.linspace(0.5,1,25)
y = np.linspace(0.5,1,25)
z = f(x,y)
surf = go.Surface(	x=x,
					y=y,
					z=z,
					contours = dict(z = dict(show=True,
							color='#111')
							)
				)
layout = go.Layout(
					scene = dict(
						zaxis = dict(
							rangemode = 'tozero'
				  		)
					)
				)
fig = go.Figure(data=[surf],layout=layout)
py.plot(fig, filename = 'bug')

With the rangemode option set to 'normal', we get the contour lines showing up as normal

But if we try to extend the z-axis to zero then the color of our contour lines changes to the colorscale of the plot. Note that in the example below the contour lines are still being plotted, their color has just changed.

I wasn't sure if this should be posted in the python or the js repo but as I found the bug in python I'm posting it here.

Best,
Peter #

[peterjbrown519]

Two further comments on this issue after more testing.

1. Setting (show = True) for either the x-axis contours or the y-axis contours stops the z-axis contours defaulting their color to the color of the surface. However, they instead default to the color of the newly-activated contours.

2. Forcing the z-axis to a range that extends beyond the surface (by plotting a single point in a scatter3d trace e.g. (0.5,0.5,0.0)) reproduces the issue. This alludes to the issue being z-axis ticks that exist beyond the range of the surface.

[jonmmease]

When I try this example with version 3.2.1 I do see contour lines in both 'normal' and 'tozero' range modes. Could you give it another try with version 3.2+? Hopefully it's just a bug that's been fixed in Plotly.js in the meantime 🙂

[jonmmease]

Closing due to lack of activity. Please open a new issue against plotly.py 3.3+ if you're still having trouble with this. Thanks!