# Usage

The parameter input for user defined material models are defined using the `*MAT_USER_[X]` command in the input deck. See the *MAT_USER_X documentation for more information.

## Start simulation with your DLL / shared object in the GUI

1. In IMPETUS Solver GUI, navigate to `Solve` and then in the Ribbon menu click on `Start simulation` button.
2. Browse for your input file.
3. Check the "Use defined material model" check box.
4. Browse for your DLL / shared object file.
5. Click `Start` button to start the simulation.

## Start simulation with your DLL / shared object in CLI

To start simulations in CLI, use the `impstart` command, which is located in `[installation_dir]/Solver/gui`. This tool add simulations to the job queue and status can be seen in the `Solve` tab of IMPETUS Solver GUI.

#### Usage

    impstart [options] INPUTFILE

Impstart is a command line tool and its options are obtained by executing it without arguments.

Use the `--material-path` option to specify where to find the material DLL / shared object file.

#### Example

    impstart --material-path /path/to/user-material.so /path/to/input-file.k