mesh_to_triangle_soup.py

#!/usr/bin/env python
import sys, random

vertices = []
faces = []

default_perturbation = 0.0

if len(sys.argv) == 4:
    perturbation = float(sys.argv[3])
elif len(sys.argv) == 3:
    perturbation = default_perturbation
    print(f"Using default perturbation amount: {perturbation}")
    sys.exit()
else:
    print(f"Usage: python distort_obj.py <input.obj> <output.obj> [<perturbation> (default: {default_perturbation})]")
    sys.exit()

with open(sys.argv[1], "r") as file:
    lines = file.read().split("\n")
    outputobj = ""
    for line in lines:
        if line.startswith("v"):
            parts = line.split(" ")
            vertices.append([float(x) for x in parts[1:]])
        if line.startswith("f"):
            parts = line.split(" ")
            faces.append([int(x) for x in parts[1:]])
    for face in faces:
        for idx in face:
            vertex = [x+random.random()*perturbation for x in vertices[idx-1]]
            outputobj += "v " + " ".join([str(x) for x in vertex]) + "\n"
    v_idx = 1
    for i in range(len(faces)):
        outputobj += "f"
        for idx in faces[i]:
            outputobj += f" {v_idx:d}"
            v_idx += 1
        outputobj += "\n"
    with open(sys.argv[2], "w") as outfile:
        outfile.write(outputobj)