Start Your First Script

Workflow

To use VifPara, you generally follow this workflow in your script. You will find variants of this workflow in all example scripts in the GitHub repository:

1. Read config Defines log/plots dir and case path

2. Load case Load the case defined in the config

3. Create layout Define how many views you want and how they are ordered

4. Create view objects Create the objects you want to view and configure them

5. Attach view modifiers Create view modifiers and attach them to the view objects (optional step)

6. Render view objects Tell the views where you want them to be in your layout

7. Export image/animation Save the layout with its views in files

Info It is important to understand how size assignment works in VifPara. When you create new views, you always assign a size in pixels to them. The layout uses those sizes to understand the relative dimensions of all views to each other. When exporting, the layout uses the height you assigned to it , to compute new sizes which fit into your provided size.

Warning The layout resizing feature is primarily here because of a behavior of ParaView. When you try to export a layout which is larger than the screen resolution of your primary display, it can lead to undesired cropping, and incorrect layout display.

Configuration

To tell your vifpara script where your testcase exists on your system, you need to provide this path to a config object in your VifPara script.

Set paths in config.json

The config.json needs to look like this:

{
   "case_path": "<path/to/your/case>",
   "dir_plots": "<path/to/your/output/image/directory>",
   "dir_logs":  "<path/to/your/log/file/directory>"
}

Use it in your script like so:

config = Config("<path/to/your/config.json>")

Info If you do not provide a parameter for read_config(), it will look for a config file called config.json in your current working directory.

Alternatively set the config directly in your Python code like so:

config = Config(custom_config = {
                  "case_path": "<path/to/your/case>",
                  "dir_plots": "<path/to/your/output/image/directory>",
                  "dir_logs":  "<path/to/your/log/file/directory>"
               })

Running a First Script

First you need to have VifPara installed in a Python environment using pip, and you need a compatible ParaView versionon your machine.

This example uses the OpenFoam motorbike testcase. Simulate it with OpenFoam. Afterwards, you point the case_path in the config to the case.foam of the testcase. If it does not exist, just create an empty file with this name in the cases root directory.

from vifpara import *

if __name__ == "__main__":
    # 1. Read config
    config = Config(custom_config = {"case_path": "tutorials/incompressible/simpleFoam/motorBike/case.foam",
                                     "dir_plots": "plots/motorBike",
                                     "dir_logs": "logs/motorBike"})
                                     
    # 2. Load case
    case = Case(config=config, case_type=CaseType.RECONSTRUCTED)
    logger.set_log_path(config.get_log_path())

    # 3. Create layout
    layout = Layout([1])

    # 4. Create view objects
    cmap = ColorMap(field="U")
    slice_obj = Slice(
        case=case,
        color_map=cmap,
        normal=Vector3(0.0, 1.0, 0.0))

    # 5. Render view objects
    slice_obj.render(layout, row=0, col=0)
    layout.set_height(800)

    # 6. Export image/animation
    exporter = Exporter(config=config, layout=layout)
    exporter.save_snapshot(filename="motorbike_slice")

Save this script as motorbike_slice.py and run it with the following line.

vifpara motorbike_slice.py

The resulting image should look like this.

For more functions and explanations consult the API Reference in this page and visit the example scripts in the GitHub page.