Apply Filter: Output

This example shows how to extract the output of a filter from the pmeshlab.MeshSet.apply_filter() function. The output of this method is a python dictionary, often empty because most of the filters do not need to return anything.

When the output dictionary is not empty, it is always on the form [key - value], where the key is of str type and the value can be a boolean, int, float or a numpy.array depending on what is best to represent the returned value. Right now the List of Filters documentation lacks on if and what type of values a filter returns (we are sorry about that!). We will expand the documentation in the future; in the meantime we suggest to look for the name and type of values returned by running the desired filter from a python console.

This script can be executed by running the following command:

pytest --pyargs pymeshlab -k 'apply_filter_output'

tests/example_apply_filter_output.py

import pymeshlab


def example_apply_filter_output():
    # lines needed to run this specific example
    print('\n')
    from . import samples_common
    base_path = samples_common.samples_absolute_path()

    # create a new MeshSet
    ms = pymeshlab.MeshSet()

    ms.load_new_mesh(base_path + "bone.ply")

    # compute the geometric measures of the current mesh
    # and save the results in the out_dict dictionary
    out_dict = ms.apply_filter('compute_geometric_measures')

    # get the average edge length from the dictionary
    avg_edge_length = out_dict['avg_edge_length']

    # get the total edge length
    total_edge_length = out_dict['total_edge_length']

    # get the mesh volume
    mesh_volume = out_dict['mesh_volume']

    # get the surface area
    surf_area = out_dict['surface_area']

    # checks with bounds (for numerical errors)
    assert (0.023 < avg_edge_length < 0.024)
    assert (105.343 < total_edge_length < 105.344)
    assert (0.025 < mesh_volume < 0.026)
    assert (0.694 < surf_area < 0.695)