mikedh
commented
1 year ago Hey, yeah it's a hand-tuned unprincipled group of properties picked for the purpose of de-duplicating meshes with identical geometry but different translation/rotation in a scene, you can see the properties listed here: https://github.com/mikedh/trimesh/blob/475f921e3497b5c360c56ff269b29c7535147f62/trimesh/comparison.py#L15-L24
It's used in scene.duplicate_nodes which is how it's able to produce results on both instanced scenes, and "bag of meshes" scenes:
import trimesh
# this is an instanced scene with for example one dowel pin transformed to multiple places
In [2]: s = trimesh.load('models/cycloidal.3DXML')
In [3]: s.duplicate_nodes
Out[3]:
[['60355K430#1:3:2:7:4:6:5',
'60355K430#1:3:2:9:8:15:14:16:4:6:5',
'60355K430#1:3:2:9:8:15:14:26:4:6:5',
'60355K430#1:3:2:9:8:27:14:16:4:6:5',
'60355K430#1:3:2:9:8:27:14:26:4:6:5',
'60355K430#1:3:2:9:8:28:14:16:4:6:5',
'60355K430#1:3:2:9:8:28:14:26:4:6:5',
'60355K430#1:3:2:42:4:6:5'],
['disc_cam_B#1:3:2:9:8:13:10:12:11'],
['camshaft#1:3:2:9:8:15:14:20:17:19:18',
'camshaft#1:3:2:9:8:27:14:20:17:19:18',
'camshaft#1:3:2:9:8:28:14:20:17:19:18'],
['vxb-6800-2rs#1:3:2:9:8:15:14:24:21:23:22',
'vxb-6800-2rs#1:3:2:9:8:15:14:25:21:23:22',
'vxb-6800-2rs#1:3:2:9:8:27:14:24:21:23:22',
'vxb-6800-2rs#1:3:2:9:8:27:14:25:21:23:22',
'vxb-6800-2rs#1:3:2:9:8:28:14:24:21:23:22',
'vxb-6800-2rs#1:3:2:9:8:28:14:25:21:23:22'],
['disc_cam_A#1:3:2:9:8:32:29:31:30'],
['92320A138_spacer#1:3:2:36:33:35:34', '92320A138_spacer#1:3:2:48:33:35:34'],
['vxb-6812RS#1:3:2:40:37:39:38', 'vxb-6812RS#1:3:2:41:37:39:38'],
['output#1:3:2:46:43:45:44', 'output#1:3:2:47:43:45:44'],
['92510A120_spacer#1:52:49:51:50',
'92510A120_spacer#1:77:49:51:50',
'92510A120_spacer#1:84:49:51:50',
'92510A120_spacer#1:85:49:51:50',
'92510A120_spacer#1:86:49:51:50'],
['bushing_roller#1:56:53:55:54',
'bushing_roller#1:70:53:55:54',
'bushing_roller#1:71:53:55:54',
'bushing_roller#1:72:53:55:54',
'bushing_roller#1:73:53:55:54',
'bushing_roller#1:74:53:55:54',
'bushing_roller#1:75:53:55:54',
'bushing_roller#1:76:53:55:54',
'bushing_roller#1:78:53:55:54',
'bushing_roller#1:79:53:55:54',
'bushing_roller#1:80:53:55:54',
'bushing_roller#1:81:53:55:54',
'bushing_roller#1:82:53:55:54',
'bushing_roller#1:83:53:55:54',
'bushing_roller#1:87:53:55:54',
'bushing_roller#1:88:53:55:54',
'bushing_roller#1:95:53:55:54',
'bushing_roller#1:99:53:55:54',
'bushing_roller#1:101:53:55:54',
'bushing_roller#1:111:53:55:54'],
['fixed_lower#1:60:57:59:58', 'fixed_top#1:68:65:67:66'],
['dowel_125#1:64:61:63:62',
'dowel_125#1:89:61:63:62',
'dowel_125#1:90:61:63:62',
'dowel_125#1:91:61:63:62',
'dowel_125#1:92:61:63:62',
'dowel_125#1:93:61:63:62',
'dowel_125#1:94:61:63:62',
'dowel_125#1:96:61:63:62',
'dowel_125#1:97:61:63:62',
'dowel_125#1:98:61:63:62',
'dowel_125#1:100:61:63:62',
'dowel_125#1:102:61:63:62',
'dowel_125#1:103:61:63:62',
'dowel_125#1:104:61:63:62',
'dowel_125#1:105:61:63:62',
'dowel_125#1:106:61:63:62',
'dowel_125#1:107:61:63:62',
'dowel_125#1:108:61:63:62',
'dowel_125#1:109:61:63:62',
'dowel_125#1:110:61:63:62']]
# this is now a scene with one mesh per position and no references
In [4]: dump = trimesh.Scene(s.dump())
In [5]: dump.duplicate_nodes
Out[5]:
[['60355K430',
'60355K430_1',
'60355K430_2',
'60355K430_3',
'60355K430_4',
'60355K430_5',
'60355K430_6',
'60355K430_7'],
['disc_cam_B'],
['camshaft', 'camshaft_1', 'camshaft_2'],
['vxb-6800-2rs',
'vxb-6800-2rs_1',
'vxb-6800-2rs_2',
'vxb-6800-2rs_3',
'vxb-6800-2rs_4',
'vxb-6800-2rs_5'],
['disc_cam_A'],
['92320A138_spacer', '92320A138_spacer_1'],
['vxb-6812RS', 'vxb-6812RS_1'],
['output', 'output_1'],
['92510A120_spacer',
'92510A120_spacer_1',
'92510A120_spacer_2',
'92510A120_spacer_3',
'92510A120_spacer_4'],
['bushing_roller',
'bushing_roller_1',
'bushing_roller_2',
'bushing_roller_3',
'bushing_roller_4',
'bushing_roller_5',
'bushing_roller_6',
'bushing_roller_7',
'bushing_roller_8',
'bushing_roller_9',
'bushing_roller_10',
'bushing_roller_11',
'bushing_roller_12',
'bushing_roller_13',
'bushing_roller_14',
'bushing_roller_15',
'bushing_roller_16',
'bushing_roller_17',
'bushing_roller_18',
'bushing_roller_19'],
['fixed_lower', 'fixed_top'],
['dowel_125',
'dowel_126',
'dowel_127',
'dowel_128',
'dowel_129',
'dowel_130',
'dowel_131',
'dowel_132',
'dowel_133',
'dowel_134',
'dowel_135',
'dowel_136',
'dowel_137',
'dowel_138',
'dowel_139',
'dowel_140',
'dowel_141',
'dowel_142',
'dowel_143',
'dowel_144']]Anecdotally it works pretty reliably but it's not based on any firm principles, just the result of experimentation.
Hello i was wondering if you would be able to explain a little more on how this is being calculated? Would similar Meshes get a similar id?