# Creating a Uniform Grid#

Create a simple uniform grid from a 3D NumPy array of values.

```import numpy as np
import pyvista as pv
```

Take a 3D NumPy array of data values that holds some spatial data where each axis corresponds to the XYZ cartesian axes. This example will create a `pyvista.UniformGrid` object that will hold the spatial reference for a 3D grid which a 3D NumPy array of values can be plotted against.

Create the 3D NumPy array of spatially referenced data. This is spatially referenced such that the grid is 20 by 5 by 10 (nx by ny by nz)

```values = np.linspace(0, 10, 1000).reshape((20, 5, 10))
values.shape
```

Create the PyVista object

```grid = pv.UniformGrid()
```
Set the grid dimensions: shape + 1 because we want to inject our values on

the CELL data

```grid.dimensions = np.array(values.shape) + 1
```

Edit the spatial reference

```grid.origin = (100, 33, 55.6)  # The bottom left corner of the data set
grid.spacing = (1, 5, 2)  # These are the cell sizes along each axis
```

Add the data values to the cell data

```grid.cell_data["values"] = values.flatten(order="F")  # Flatten the array!
grid
```

Now plot the grid!

```grid.plot(show_edges=True)
```

Don’t like cell data? You could also add the NumPy array to the point data of a `pyvista.UniformGrid`. Take note of the subtle difference when setting the grid dimensions upon initialization.

```# Create the 3D NumPy array of spatially referenced data
# This is spatially referenced such that the grid is 20 by 5 by 10
#   (nx by ny by nz)
values = np.linspace(0, 10, 1000).reshape((20, 5, 10))
values.shape
```

Create the PyVista object and set the same attributes like above

```grid = pv.UniformGrid()

# Set the grid dimensions: shape because we want to inject our values on the
#   POINT data
grid.dimensions = values.shape

# Edit the spatial reference
grid.origin = (100, 33, 55.6)  # The bottom left corner of the data set
grid.spacing = (1, 5, 2)  # These are the cell sizes along each axis
```

Add the data values to the cell data

```grid.point_data["values"] = values.flatten(order="F")  # Flatten the array!
grid
```

Now plot the grid!

```grid.plot(show_edges=True)
```

## Exercise#

Now create your own `pyvista.UniformGrid` from a 3D NumPy array!

```help(pv.UniformGrid)
```

Here are some example 3D data using random data. Feel free to use your own 3D numpy array here!

```arr = np.random.random((100, 100, 100))
arr.shape
```

Create the `pyvista.UniformGrid`

Hint, you will likely need to `ravel` the array with F-ordering: `arr.ravel(order="F")`

```vol = pv.UniformGrid()
# Set attributes and data
...
```
```vol.plot()
```

## Example#

Here are some examples of this kind of data in PyVista!

See the PyVista documentation for further details on Volume Rendering

```from pyvista import examples

```vol = pv.Wavelet()