title: Python 3d plot set fixed colorscales
body: <p>I am trying to plot two 3d arrays: the first has (z) values in range <code>[-0.15, 0.15]</code> , the second one from <code>[-0.001, 0.001]</code>. When I plot, the colorscales automatically follows the datarange: how can I set a custom scale instead? I don't want to see light color for 0.001 as instead should be for 0.15. How can I fix the scale?</p>
  
  <p>I share the partial code below:</p>
  
  <pre><code>import numpy as np 
  import matplotlib.pyplot as plt 
  import plotly.graph_objects as go
  
  
  data1=np.load("test.npy")
  fig = go.Figure(data=[go.Surface(z=data1,colorscale="viridis")])
  
  
  fig.update_layout(margin = dict(t=100,r=100,b=100,l=100),
      scene = dict(zaxis = dict(range=[-0.15,0.15],)),
      showlegend = False,
      width = 1000, height = 1000,
      autosize = False )
  fig.update_layout(scene = dict(
                      xaxis_title='x',
                      yaxis_title='y',
                      zaxis_title='z'))
  fig.write_image("image.pdf")
  fig.show()
  
  </code></pre>