plotly · emmanuelle · Sep 4, 2019 · Sep 4, 2019 · Sep 4, 2019
diff --git a/python/3d-isosurface-plots.md b/python/3d-isosurface-plots.md
@@ -0,0 +1,242 @@
+---
+jupyter:
+  jupytext:
+    notebook_metadata_filter: all
+    text_representation:
+      extension: .md
+      format_name: markdown
+      format_version: '1.1'
+      jupytext_version: 1.1.1
+  kernelspec:
+    display_name: Python 3
+    language: python
+    name: python3
+  language_info:
+    codemirror_mode:
+      name: ipython
+      version: 3
+    file_extension: .py
+    mimetype: text/x-python
+    name: python
+    nbconvert_exporter: python
+    pygments_lexer: ipython3
+    version: 3.7.3
+  plotly:
+    description: How to make 3D Isosurface Plots in Python with Plotly.
+    display_as: 3d_charts
+    has_thumbnail: true
+    ipynb: ~notebook_demo/272
+    language: python
+    layout: user-guide
+    name: 3D Isosurface Plots
+    order: 12.1
+    page_type: u-guide
+    permalink: python/3d-isosurface-plots/
+    redirect_from: python/isosurfaces-with-marching-cubes/
+    thumbnail: thumbnail/isosurface.jpg
+    title: Python 3D Isosurface Plots | plotly
+---
+
+With ``go.Isosurface``, you can plot [isosurface contours](https://en.wikipedia.org/wiki/Isosurface) of a scalar field ``value``, which is defined on ``x``, ``y`` and ``z`` coordinates.
+
+#### Basic Isosurface
+
+In this first example, we plot the isocontours of values ``isomin=2`` and ``isomax=6``. In addition, portions of the sides of the coordinate domains for which the value is between ``isomin`` and ``isomax`` (named the ``caps``) are colored. Please rotate the figure to visualize both the internal surfaces and the caps surfaces on the sides.
+
+```python
+import plotly.graph_objects as go
+
+fig= go.Figure(data=go.Isosurface(
+    x=[0,0,0,0,1,1,1,1],
+    y=[1,0,1,0,1,0,1,0],
+    z=[1,1,0,0,1,1,0,0],
+    value=[1,2,3,4,5,6,7,8],
+    isomin=2,
+    isomax=6,
+))
+
+fig.show()
+```
+
+### Removing caps when visualizing isosurfaces
+
+For a clearer visualization of internal surfaces, it is possible to remove the caps (color-coded surfaces on the sides of the visualization domain). Caps are visible by default.
+
+```python
+import plotly.graph_objects as go
+import numpy as np
+
+X, Y, Z = np.mgrid[-5:5:40j, -5:5:40j, -5:5:40j]
+
+# ellipsoid 
+values = X * X * 0.5 + Y * Y + Z * Z * 2
+
+fig = go.Figure(data=go.Isosurface(
+    x=X.flatten(),
+    y=Y.flatten(),
+    z=Z.flatten(),
+    value=values.flatten(),
+    isomin=10,
+    isomax=40,
+    caps=dict(x_show=False, y_show=False)
+    ))
+fig.show()
+```
+
+### Modifying the number of isosurfaces
+
+```python
+import plotly.graph_objects as go
+import numpy as np
+
+X, Y, Z = np.mgrid[-5:5:40j, -5:5:40j, -5:5:40j]
+
+# ellipsoid 
+values = X * X * 0.5 + Y * Y + Z * Z * 2
+
+fig = go.Figure(data=go.Isosurface(
+    x=X.flatten(),
+    y=Y.flatten(),
+    z=Z.flatten(),
+    value=values.flatten(),
+    isomin=10,
+    isomax=50,
+    surface_count=5, # number of isosurfaces, 2 by default: only min and max
+    colorbar_nticks=5, # colorbar ticks correspond to isosurface values
+    caps=dict(x_show=False, y_show=False)
+    ))
+fig.show()
+```
+
+### Changing the opacity of isosurfaces
+
+```python
+import plotly.graph_objects as go
+import numpy as np
+
+X, Y, Z = np.mgrid[-5:5:40j, -5:5:40j, -5:5:40j]
+
+# ellipsoid 
+values = X * X * 0.5 + Y * Y + Z * Z * 2
+
+fig = go.Figure(data=go.Isosurface(
+    x=X.flatten(),
+    y=Y.flatten(),
+    z=Z.flatten(),
+    value=values.flatten(),
+    opacity=0.6,
+    isomin=10,
+    isomax=50,
+    surface_count=3,
+    caps=dict(x_show=False, y_show=False)
+    ))
+fig.show()
+```
+
+#### Isosurface with Addtional Slices
+
+Here we visualize slices parallel to the axes on top of isosurfaces. For a clearer visualization, the `fill` ratio of isosurfaces is decreased below 1 (completely filled). 
+
+```python
+import plotly.graph_objects as go
+import numpy as np
+
+X, Y, Z = np.mgrid[-5:5:40j, -5:5:40j, -5:5:40j]
+
+# ellipsoid 
+values = X * X * 0.5 + Y * Y + Z * Z * 2
+
+fig = go.Figure(data=go.Isosurface(
+    x=X.flatten(),
+    y=Y.flatten(),
+    z=Z.flatten(),
+    value=values.flatten(),
+    isomin=5,
+    isomax=50,
+    surface_fill=0.4,
+    caps=dict(x_show=False, y_show=False),
+    slices_z=dict(show=True, locations=[-1, -3,]),
+    slices_y=dict(show=True, locations=[0]),
+    ))
+fig.show()
+```
+
+#### Multiple Isosurfaces with Caps
+
+```python
+import plotly.graph_objects as go
+import numpy as np
+
+X, Y, Z = np.mgrid[-5:5:40j, -5:5:40j, 0:5:20j]
+
+values = X * X * 0.5 + Y * Y + Z * Z * 2
+
+fig = go.Figure(data=go.Isosurface(
+    x=X.flatten(),
+    y=Y.flatten(),
+    z=Z.flatten(),
+    value=values.flatten(),
+    isomin=30,
+    isomax=50,
+    surface=dict(count=3, fill=0.7, pattern='odd'),
+    caps=dict(x_show=True, y_show=True),
+    ))
+fig.show()
+```
+
+### Changing the default colorscale of isosurfaces
+
+```python
+import plotly.graph_objects as go
+import numpy as np
+
+X, Y, Z = np.mgrid[-5:5:40j, -5:5:40j, -5:5:40j]
+
+# ellipsoid 
+values = X * X * 0.5 + Y * Y + Z * Z * 2
+
+fig = go.Figure(data=go.Isosurface(
+    x=X.flatten(),
+    y=Y.flatten(),
+    z=Z.flatten(),
+    value=values.flatten(),
+    colorscale='BlueRed',
+    isomin=10,
+    isomax=50,
+    surface_count=3,
+    caps=dict(x_show=False, y_show=False)
+    ))
+fig.show()
+```
+
+### Customizing the layout and appearance of isosurface plots
+
+```python
+import plotly.graph_objects as go
+import numpy as np
+
+X, Y, Z = np.mgrid[-5:5:40j, -5:5:40j, 0:5:20j]
+
+values = X * X * 0.5 + Y * Y + Z * Z * 2
+
+fig = go.Figure(data=go.Isosurface(
+    x=X.flatten(),
+    y=Y.flatten(),
+    z=Z.flatten(),
+    value=values.flatten(),
+    isomin=30,
+    isomax=50,
+    surface=dict(count=3, fill=0.7, pattern='odd'),
+    showscale=False, # remove colorbar
+    caps=dict(x_show=True, y_show=True),
+    ))
+
+fig.update_layout(
+    margin=dict(t=0, l=0, b=0), # tight layout
+    scene_camera_eye=dict(x=1.86, y=0.61, z=0.98))
+fig.show()
+```
+
+#### Reference
+See https://plot.ly/python/reference/#isosurface for more information and chart attribute options!
+