Plotly - different color surfaces

The documentation is a bit cryptic here.

surfacecolor

(list, numpy array, or Pandas series of numbers, strings, or datetimes.)

Sets the surface color values, used for setting a color scale independent of z.

I never managed to put a list of strings, i.e. color values like 'rgb(0.3, 0.5, 0)', or RGB tuples in it.

But you can define your own color scale with the needed colors.

colorscale = [[0, 'rgb' + str(cmap(1)[0:3])], 
              [1, 'rgb' + str(cmap(2)[0:3])]]

and then provide a numeric array with the same dimensions as your plotted values.

colors_saddle = np.zeros(shape=saddle.shape)    

All values are set to 0 and will therefore map to the first color in your colorscale. The same for the next color.

In addition you need to set cmax and cmin manually.

Complete code

import numpy as np
import matplotlib.pyplot as plt
import plotly.graph_objs as go
import plotly.offline as off


off.init_notebook_mode()

make_int = np.vectorize(int)
cmap = plt.get_cmap("tab10")

saddle = np.array([[x**2-y**2 for x in np.arange(-10,11)] for y in np.arange(-10,11)])
paraboloid = np.array([[x**2 + y**2-100 for x in np.arange(-10,11)] for y in np.arange(-10,11)])

colors_saddle = np.zeros(shape=saddle.shape)    
colors_paraboloid = np.ones(shape=paraboloid.shape)    

colorscale = [[0, 'rgb' + str(cmap(1)[0:3])], 
              [1, 'rgb' + str(cmap(2)[0:3])]]

trace_a = go.Surface(z=saddle, 
                     surfacecolor=colors_saddle, 
                     opacity=.7, 
                     name="Trace A",
                     cmin=0,
                     cmax=1,
                     colorscale=colorscale)
trace_b = go.Surface(z=paraboloid, 
                     surfacecolor=colors_paraboloid, 
                     opacity=.7, 
                     name="Trace B", 
                     cmin=0,
                     cmax=1,
                     showscale=False,
                     colorscale=colorscale)

data = [trace_a, trace_b]
off.iplot(data)