moving models by matching inner surface

Hi @mikedh ,

Thank you for replying #1383. But this just combine the both models but they are not fitting on model1 by matching the inner surface of model2 to outer surface of model1. I have the both pictures one is what I am getting with this code that you have suggested and the second is expected result.

If we have transformation which can work on surfaces not on the Bounding Box then it may work but I am not sure.

Thank you for helping, Akshay

Python 3.8.8 (default, Apr 13 2021, 15:08:03) [MSC v.1916 64 bit (AMD64)]
Type "copyright", "credits" or "license" for more information.

IPython 7.22.0 -- An enhanced Interactive Python.

import numpy as np

import trimesh

a = trimesh.load('model1.stl')

b = trimesh.load('model2.stl')
Data not utf-8! Trying Windows-1252 (confidence 0.73)

at = a.bounding_box_oriented.primitive.transform

bt = b.bounding_box_oriented.primitive.transform

a_to_b = np.dot(bt, np.linalg.inv(at))

at
Out[8]: 
TrackedArray([[-0.92817622, -0.35878948, -0.09878775,  3.17065155],
              [-0.06162009, -0.1136176 ,  0.99161182, 39.2899497 ],
              [-0.36700392,  0.92647782,  0.08334852,  2.22560429],
              [ 0.        ,  0.        ,  0.        ,  1.        ]])

a.bounds
Out[9]: 
array([[-4.58730364, 30.99465752, -6.10579252],
       [ 9.77338219, 48.5644455 , 11.24947166]])

b.bounds
Out[10]: 
array([[-4.66867018, -6.44354057, -4.65808773],
       [ 5.90229559,  6.26821184,  3.41614819]])

a.apply_transform(a_to_b)
Out[11]: <trimesh.Trimesh(vertices.shape=(38137, 3), faces.shape=(75908, 3))>

a.bounds
Out[12]: 
array([[-10.03075575, -10.71799307,  -7.50492806],
       [  6.82770259,   7.95139979,   4.4296185 ]])

b.bounds
Out[13]: 
array([[-4.66867018, -6.44354057, -4.65808773],
       [ 5.90229559,  6.26821184,  3.41614819]])

Capture4

Originally posted by @akshaypatel1811 in https://github.com/mikedh/trimesh/issues/1383#issuecomment-947758273

mikedh / trimesh

moving models by matching inner surface #1387