pyfqmr-withuvs 0.2.1
cython wrapper around C++ library for fast triangular mesh reduction
License: MIT

pyfqmr : Python Fast Quadric Mesh Reduction
===========================================

Cython wrapper around `sp4acerat's quadrics mesh reduction
algorithm <https://github.com/sp4cerat/Fast-Quadric-Mesh-Simplification>`__.

Requirements:
~~~~~~~~~~~~~

-  *Numpy*
-  *Cython* (only for compilation, but not needed if installed from PyPI)

Installation :
~~~~~~~~~~~~~~
pyfqmr can be installed via  `pip <https://pypi.org/project/pyfqmr/0.1.1/>`_ :


.. code:: bash

    pip install pyfqmr


Compilation :
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Run:

.. code:: bash

    python setup.py install

Usage:
~~~~~~

.. code:: python

    >>> #We assume you have a numpy based mesh processing software
    >>> #Where you can get the vertices and faces of the mesh as numpy arrays.
    >>> #For example Trimesh or meshio
    >>> import pyfqmr
    >>> import trimesh as tr
    >>> bunny = tr.load_mesh('example/Stanford_Bunny_sample.stl')
    >>> #Simplify object
    >>> mesh_simplifier = pyfqmr.Simplify()
    >>> mesh_simplifier.setMesh(bunny.vertices, bunny.faces)
    >>> mesh_simplifier.simplify_mesh(target_count = 1000, aggressiveness=7, preserve_border=True, verbose=10)
    iteration 0 - triangles 112402 threshold 2.187e-06
    iteration 5 - triangles 62674 threshold 0.00209715
    iteration 10 - triangles 21518 threshold 0.0627485
    iteration 15 - triangles 9086 threshold 0.61222
    iteration 20 - triangles 4692 threshold 3.40483
    iteration 25 - triangles 2796 threshold 13.4929
    iteration 30 - triangles 1812 threshold 42.6184
    iteration 35 - triangles 1262 threshold 114.416
    simplified mesh in 0.2518 seconds 
    >>> vertices, faces, normals = mesh_simplifier.getMesh()

Controlling the reduction algorithm
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Parameters of the '''simplify\_mesh''' method that can be tuned.

-  **target\_count**
    Target number of triangles.
-  **update\_rate**
    Number of iterations between each update.
-  **max\_iterations**
    Maximal number of iterations
-  **aggressiveness**
    Parameter controlling the growth rate of the threshold at each iteration when lossless is False.
-  **preserve\_border**
    Flag for preserving the vertices situated on open borders. Applies the method described in `this issue <https://github.com/sp4cerat/Fast-Quadric-Mesh-Simplification/issues/14>`__.
-  **alpha**
    Parameter for controlling the threshold growth. Exact implication described below.
-  **K**
    Parameter for controlling the threshold growth. Exact implication described below.
-  **lossless**
    Flag for using the lossless simplification method. Sets the update rate to 1 .
-  **threshold\_lossless**
    Maximal error after which a vertex is not deleted, only when the lossless flag is set to True.
-  **verbose**
    Controls verbosity

Implications of the parameters of the threshold growth rate (when not in lossless mode) :
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
$$threshold = alpha \* (iteration + K)^{agressiveness}$$

\

More information is to be found on Sp4cerat's repository : `Fast-Quadric-Mesh-Simplification <https://github.com/sp4cerat/Fast-Quadric-Mesh-Simplification>`__

Huge thanks to Sp4cerat for making his code available!