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# Modeling: Using design parameters

You can read and update parameters that are part of the design.
The simple design in this example has two associated parameters.

+++

## Perform required imports

```{code-cell} ipython3
from pathlib import Path
import requests

from ansys.geometry.core import launch_modeler
```

The file for this example is in the integration tests folder and can be downloaded.

+++

## Download the example file

+++

Download the file for this example from the integration tests folder in the PyAnsys Geometry repository.

```{code-cell} ipython3
def download_file(url, filename):
    """Download a file from a URL and save it to a local file."""
    response = requests.get(url)
    response.raise_for_status()  # Check if the request was successful
    with open(filename, 'wb') as file:
        file.write(response.content)

# URL of the file to download
url = "https://raw.githubusercontent.com/ansys/pyansys-geometry/main/tests/integration/files/blockswithparameters.dsco"

# Local path to save the file to
file_path = Path.cwd() / "blockswithparameters.dsco"

# Download the file
download_file(url, file_path)
print(f"File is downloaded to {file_path}")
```

## Import a design with parameters

+++

Import the model using the ``open_file()`` method of the modeler.

```{code-cell} ipython3
# Create a modeler object
modeler = launch_modeler()
design = modeler.open_file(file_path)
design.plot()
```

## Read existing parameters of the design

You can get all the parameters of the design as a list of parameters. Because this
example has two parameters, you see two items in the list.

```{code-cell} ipython3
my_parameters = design.parameters
print(len(my_parameters))
```

A parameter object has a name, value, and unit.

```{code-cell} ipython3
print(my_parameters[0].name)
print(my_parameters[0].dimension_value)
print(my_parameters[0].dimension_type)

print(my_parameters[1].name)
print(my_parameters[1].dimension_value)
print(my_parameters[1].dimension_type)
```

Parameter values are returned in the default unit for each dimension type. Since default length
unit is meter and default area unit is meter square, the value is returned in square meters.

+++

## Edit a parameter value

You can edit the parameter's name or value by simply setting these fields.
Set the second parameter (p2 value to 350 mm).

```{code-cell} ipython3
parameter1 = my_parameters[1]
parameter1.dimension_value = 0.000440
response = design.set_parameter(parameter1)
print(response)
print(my_parameters[0].dimension_value)
print(my_parameters[1].dimension_value)
```

After a successful parameter update, the design is updated. If we request the design
plot again, we see the updated design.

```{code-cell} ipython3
design.plot()
```

The ``set_parameter()`` method returns a ``Success`` status message if the parameter is updated or
a "FAILURE" status message if the update fails. If the ``p2`` parameter depends on the ``p1``
parameter, updating the ``p1`` parameter might also change the ``p2`` parameter. In such cases,
the method returns ``CONSTRAINED_PARAMETERS``, which indicates other parameters were also updated.

```{code-cell} ipython3
parameter1 = my_parameters[0]
parameter1.dimension_value = 0.000250
response = design.set_parameter(parameter1)
print(response)
```

To get the updated list, query the parameters once again.

```{code-cell} ipython3
my_parameters = design.parameters
print(my_parameters[0].dimension_value)
print(my_parameters[1].dimension_value)
```

## Close the modeler

Close the modeler to free up resources and release the connection.

```{code-cell} ipython3
modeler.close()
```