edge-distance based mesh cleanup

script.py

import bpy
import bmesh
import numpy as np
from math import radians

MERGE_THRESHOLD = 0.01
DISSOLVE_ANGLE = 0.5
MAX_ITER = 10


def distance_from_line(p, q, rs, oobval):
    x = p - q
    shifted_points = rs - q
    projections = np.dot(shifted_points, x)
    x_magnitude_squared = np.dot(x, x)
    scaling_factors = projections / x_magnitude_squared
    
    in_bounds = (scaling_factors >= 0) & (scaling_factors <= 1)
    scaling_factors = scaling_factors[in_bounds]     
    projected_points = np.outer(scaling_factors, x) + q - rs[in_bounds]
    distances = np.full((rs.shape[0],), oobval, dtype=np.float64)
    distances[in_bounds] = np.linalg.norm(projected_points, axis=1)
    
    return distances


def closest_point_parameter(a, b, x):
    ab = b - a
    ax = x - a
    t = np.dot(ax, ab) / np.dot(ab, ab)
    return t


obj = bpy.context.edit_object
me = obj.data


for i in range(MAX_ITER):
    bm = bmesh.from_edit_mesh(me)
    bm.verts.ensure_lookup_table()
    
    print(f'Iter {i}.  Verts: {len(bm.verts)}.  Edges: {len(bm.edges)}')

    edge_as = []
    edge_bs = []

    verts = np.array([v.co for v in bm.verts])
    vert_idxs = np.arange(len(bm.verts))

    edge_percents = {}

    for edge in bm.edges:
        e_a, e_b = edge.verts
        a = np.array(e_a.co)
        b = np.array(e_b.co)
        
        vert_mask = np.all(verts == a, axis=1) | np.all(verts == b, axis=1)
        other_verts = verts[~vert_mask]

        dists = distance_from_line(a, b, other_verts, MERGE_THRESHOLD * 10)
        
        min_dist_idx = np.argmin(dists)
        if dists[min_dist_idx] < MERGE_THRESHOLD:
            vert_idx = vert_idxs[~vert_mask][min_dist_idx]
            vert = bm.verts[vert_idx]
            
            percent = closest_point_parameter(a, b, other_verts[min_dist_idx])
            edge_percents[edge] = percent

    if not edge_percents:
        break
    bmesh.ops.subdivide_edges(bm, edges=list(edge_percents.keys()), cuts=1, edge_percents=edge_percents)
    bmesh.update_edit_mesh(me, loop_triangles=True)

    bpy.ops.mesh.remove_doubles(threshold=MERGE_THRESHOLD, use_unselected=True)
    bpy.ops.mesh.select_all(action='DESELECT')
    bpy.ops.mesh.select_mode(type = 'FACE')
    bpy.ops.mesh.select_interior_faces()
    bpy.ops.mesh.delete(type='FACE')
    bpy.ops.mesh.select_all(action='SELECT')
    bpy.ops.mesh.dissolve_limited(angle_limit=radians(DISSOLVE_ANGLE))
    
    
print('DONE')