stl_combine.py

import numpy as np
import shutil
import math
import subprocess
import stl
import os
from stl import mesh
from colorama import Fore, Back, Style


def load_mesh(stl_file):
    return mesh.Mesh.from_file(stl_file)


def save_mesh(mesh, stl_file):
    mesh.save(stl_file, mode=stl.Mode.BINARY)


def combine_meshes(m1, m2):
    return mesh.Mesh(np.concatenate([m1.data, m2.data]))


def apply_matrix(mesh, matrix):
    rotation = matrix[0:3, 0:3]
    translation = matrix[0:3, 3:4].T.tolist()

    def transform(points):
        return (rotation*np.matrix(points).T).T + translation*len(points)

    mesh.v0 = transform(mesh.v0)
    mesh.v1 = transform(mesh.v1)
    mesh.v2 = transform(mesh.v2)
    mesh.normals = transform(mesh.normals)


# Script taken from doing the needed operation
# (Filters > Remeshing, Simplification and Reconstruction >
# Quadric Edge Collapse Decimation, with parameters:
# 0.9 percentage reduction (10%), 0.3 Quality threshold (70%)
# Target number of faces is ignored with those parameters
# conserving face normals, planar simplification and
# post-simplimfication cleaning)
# And going to Filter > Show current filter script
filter_script_mlx = """
<!DOCTYPE FilterScript>
<FilterScript>
<filter name="Simplification: Quadric Edge Collapse Decimation">

<Param type="RichFloat" value="%reduction%" name="TargetPerc"/>
<Param type="RichFloat" value="0.5" name="QualityThr"/>
<Param type="RichBool" value="false" name="PreserveBoundary"/>
<Param type="RichFloat" value="1" name="BoundaryWeight"/>
<Param type="RichBool" value="true" name="PreserveNormal"/>
<Param type="RichBool" value="false" name="PreserveTopology"/>
<Param type="RichBool" value="true" name="OptimalPlacement"/>
<Param type="RichBool" value="true" name="PlanarQuadric"/>
<Param type="RichBool" value="false" name="QualityWeight"/>
<Param type="RichFloat" value="0.001" name="PlanarWeight"/>
<Param type="RichBool" value="true" name="AutoClean"/>
<Param type="RichBool" value="false" name="Selected"/>


</filter>
</FilterScript>
"""


def create_tmp_filter_file(filename='filter_file_tmp.mlx', reduction=0.9):
    with open('/tmp/' + filename, 'w', encoding="utf-8") as stream:
        stream.write(filter_script_mlx.replace('%reduction%', str(reduction)))
    return '/tmp/' + filename


def reduce_faces(in_file, out_file, reduction=0.5):
    filter_script_path = create_tmp_filter_file(reduction=reduction)
    # Add input mesh
    command = "meshlabserver -i " + in_file
    # Add the filter script
    command += " -s " + filter_script_path
    # Add the output filename and output flags
    command += " -o " + out_file 
    command += " > /tmp/meshlab.log 2>&1"
    # Execute command
    # print("Going to execute: " + command)
    output = subprocess.check_output(command, shell=True)
    # last_line = output.splitlines()[-1]
    # print("Done:")
    #print(in_file + " > " + out_file + ": " + last_line)


def simplify_stl(stl_file, max_size=3):
    size_M = os.path.getsize(stl_file)/(1024*1024)

    if size_M > max_size:
        print(Fore.BLUE + '+ '+os.path.basename(stl_file) +
              (' is %.2f M, running mesh simplification' % size_M))
        shutil.copyfile(stl_file, '/tmp/simplify.stl')
        reduce_faces('/tmp/simplify.stl', stl_file, max_size / size_M)