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plotly:
description: How to make 3D Mesh Plots
display_as: 3d_charts
language: python
layout: base
name: 3D Mesh Plots
order: 9
page_type: u-guide
permalink: python/3d-mesh/
thumbnail: thumbnail/3d-mesh.jpg
---
### Simple 3D Mesh example ###
`go.Mesh3d` draws a 3D set of triangles with vertices given by `x`, `y` and `z`. If only coordinates are given, an algorithm such as [Delaunay triangulation](https://en.wikipedia.org/wiki/Delaunay_triangulation) is used to draw the triangles. Otherwise the triangles can be given using the `i`, `j` and `k` parameters (see examples below).
```python
import plotly.graph_objects as go
import numpy as np
# Download data set from plotly repo
pts = np.loadtxt(np.DataSource().open('https://raw.githubusercontent.com/plotly/datasets/master/mesh_dataset.txt'))
x, y, z = pts.T
fig = go.Figure(data=[go.Mesh3d(x=x, y=y, z=z, color='lightpink', opacity=0.50)])
fig.show()
```
### 3D Mesh example with Alphahull
The `alphahull` parameter sets the shape of the mesh. If the value is -1 (default value) then [Delaunay triangulation](https://en.wikipedia.org/wiki/Delaunay_triangulation) is used. If >0 then the [alpha-shape algorithm](https://en.wikipedia.org/wiki/Alpha_shape) is used. If 0, the [convex hull](https://en.wikipedia.org/wiki/Convex_hull) is represented (resulting in a convex body).
```python
import plotly.graph_objects as go
import numpy as np
pts = np.loadtxt(np.DataSource().open('https://raw.githubusercontent.com/plotly/datasets/master/mesh_dataset.txt'))
x, y, z = pts.T
fig = go.Figure(data=[go.Mesh3d(x=x, y=y, z=z,
alphahull=5,
opacity=0.4,
color='cyan')])
fig.show()
```
### 3D Mesh in Dash
[Dash](https://plotly.com/dash/) is the best way to build analytical apps in Python using Plotly figures. To run the app below, run `pip install dash`, click "Download" to get the code and run `python app.py`.
Get started with [the official Dash docs](https://dash.plotly.com/installation) and **learn how to effortlessly [style](https://plotly.com/dash/design-kit/) & [deploy](https://plotly.com/dash/app-manager/) apps like this with Dash Enterprise.**
```python hide_code=true
from IPython.display import IFrame
snippet_url = 'https://python-docs-dash-snippets.herokuapp.com/python-docs-dash-snippets/'
IFrame(snippet_url + '3d-mesh', width='100%', height=1200)
```
Sign up for Dash Club → Free cheat sheets plus updates from Chris Parmer and Adam Schroeder delivered to your inbox every two months. Includes tips and tricks, community apps, and deep dives into the Dash architecture.
Join now.
### Mesh Tetrahedron
In this example we use the `i`, `j` and `k` parameters to specify manually the geometry of the triangles of the mesh.
```python
import plotly.graph_objects as go
fig = go.Figure(data=[
go.Mesh3d(
x=[0, 1, 2, 0],
y=[0, 0, 1, 2],
z=[0, 2, 0, 1],
colorbar=dict(title=dict(text='z')),
colorscale=[[0, 'gold'],
[0.5, 'mediumturquoise'],
[1, 'magenta']],
# Intensity of each vertex, which will be interpolated and color-coded
intensity=[0, 0.33, 0.66, 1],
# i, j and k give the vertices of triangles
# here we represent the 4 triangles of the tetrahedron surface
i=[0, 0, 0, 1],
j=[1, 2, 3, 2],
k=[2, 3, 1, 3],
name='y',
showscale=True
)
])
fig.show()
```
### Mesh Cube
```python
import plotly.graph_objects as go
import numpy as np
fig = go.Figure(data=[
go.Mesh3d(
# 8 vertices of a cube
x=[0, 0, 1, 1, 0, 0, 1, 1],
y=[0, 1, 1, 0, 0, 1, 1, 0],
z=[0, 0, 0, 0, 1, 1, 1, 1],
colorbar=dict(title=dict(text='z')),
colorscale=[[0, 'gold'],
[0.5, 'mediumturquoise'],
[1, 'magenta']],
# Intensity of each vertex, which will be interpolated and color-coded
intensity = np.linspace(0, 1, 8, endpoint=True),
# i, j and k give the vertices of triangles
i = [7, 0, 0, 0, 4, 4, 6, 6, 4, 0, 3, 2],
j = [3, 4, 1, 2, 5, 6, 5, 2, 0, 1, 6, 3],
k = [0, 7, 2, 3, 6, 7, 1, 1, 5, 5, 7, 6],
name='y',
showscale=True
)
])
fig.show()
```
### Intensity values defined on vertices or cells
The `intensitymode` attribute of `go.Mesh3d` can be set to `vertex` (default mode, in which case intensity values are interpolated between values defined on vertices), or to `cell` (value of the whole cell, no interpolation). Note that the `intensity` parameter should have the same length as the number of vertices or cells, depending on the `intensitymode`.
Whereas the previous example used the default `intensitymode='vertex'`, we plot here the same mesh with `intensitymode='cell'`.
```python
import plotly.graph_objects as go
fig = go.Figure(data=[
go.Mesh3d(
# 8 vertices of a cube
x=[0, 0, 1, 1, 0, 0, 1, 1],
y=[0, 1, 1, 0, 0, 1, 1, 0],
z=[0, 0, 0, 0, 1, 1, 1, 1],
colorbar=dict(title=dict(text='z')),
colorscale=[[0, 'gold'],
[0.5, 'mediumturquoise'],
[1, 'magenta']],
# Intensity of each vertex, which will be interpolated and color-coded
intensity = np.linspace(0, 1, 12, endpoint=True),
intensitymode='cell',
# i, j and k give the vertices of triangles
i = [7, 0, 0, 0, 4, 4, 6, 6, 4, 0, 3, 2],
j = [3, 4, 1, 2, 5, 6, 5, 2, 0, 1, 6, 3],
k = [0, 7, 2, 3, 6, 7, 1, 1, 5, 5, 7, 6],
name='y',
showscale=True
)
])
fig.show()
```
## Reference
See https://plotly.com/python/reference/mesh3d/ for more information and chart attribute options!