pyfqmr 0.2.1

cython wrapper around C++ library for fast triangular mesh reduction

Cython wrapper around sp4acerat’s quadrics mesh reduction algorithm.

Requirements:

• Numpy

• Cython (only for compilation, but not needed if installed from PyPI)

Installation :

pyfqmr can be installed via pip :

pip install pyfqmr

Compilation :

Run:

python setup.py install

Usage:

>>> #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.

• 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

Huge thanks to Sp4cerat for making his code available!