fix 5091. Add a Node center of mass for a one or multiple meshes #5092
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…total center - append docs for this node (without example)
| @@ -0,0 +1,79 @@ | |||
| Weighted Vector Sum (Alpha) | |||
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I would suggest to name the node "Center of Mass - Mesh" (as opposed to existing Center of Mass node for solids; maybe that node should be renamed to "Center of Mass - Solid", for clarity).
| class SvWeightedVectorSumNode(SverchCustomTreeNode, bpy.types.Node, SvRecursiveNode): | ||
| """ | ||
| Triggers: Bbox 2D or 3D | ||
| Tooltip: Get vertices bounding box (vertices, sizes, center) |
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needs update after copy-paste :)
| description="Polygons processing mode", | ||
| items=ngon_modes, | ||
| default="BEAUTY", | ||
| update=updateNode) # type: ignore |
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I'd suggest to add a checkbox to disable triangulation at all (maybe hide it to the N panel). In case the user knows that the mesh is already tris-only.
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If mode is 'Face' then one can check all faces are tris without any property:
but for mode 'Volume' it is not enough: mesh has to be closed and this is a difficult operation. I have suggestion for property 'skip_test_volume_are_closed' and this do real economy for "Volume" mode:
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But this mode do triangulation if some faces are not tris and this back to slowdown performance but user get good result.
| area_I = areases_I.sum() | ||
| tris_centers_I = tris_I.sum(axis=1) / 3.0 | ||
| center_mass_mesh_I = (tris_centers_I * areases_I[np.newaxis].T).sum(axis=0) / area_I | ||
| mass_I = area_I * density_I[0] |
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I'd say core algorithms should be moved to sverchok.utils.geom, and just be called from the node.
| volume_I = signed_volumes_I.sum() | ||
| tetra_centers_I = tris_I.sum(axis=1) / 4.0 | ||
| center_mass_mesh_I = (tetra_centers_I * signed_volumes_I[np.newaxis].T).sum(axis=0) / volume_I | ||
| mass_I = volume_I * density_I[0] |
| self.outputs['output_edges'] .label = 'Edges' | ||
| self.outputs['output_polygons'] .label = 'Polygons' | ||
| self.outputs['output_centers_of_mass'].label = 'Centers mass of objects' | ||
| self.outputs['output_total_center'].label = 'Total center' |
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So many centers. I mean “Center of all objects”. May be last is good?
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Is it good?
To see changes you need recreate node.
| self.outputs['output_vertices'] .label = 'Vertices' | ||
| self.outputs['output_edges'] .label = 'Edges' | ||
| self.outputs['output_polygons'] .label = 'Polygons' | ||
| self.outputs['output_centers_of_mass'].label = 'Centers mass of objects' |
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"Centers of mass of objects"
| # test if all edges are contiguous (https://docs.blender.org/api/current/bmesh.types.html#bmesh.types.BMEdge.is_contiguous) | ||
| # then volume is closed: | ||
| for edge in bm_I.edges: | ||
| if edge.is_contiguous==False: |
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Also probably needs a flag to disable this check. If the user already knows the volume is closed, this is just a waste of time.
- rename node name in menu - append a param skip_test_volume_are_closed (only for volume mode) - append test triangulation before call bmesh utils for Face and Volume modes
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for tests: |
utils/sv_bmesh_utils.py
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| @@ -912,3 +913,186 @@ def recalc_normals(verts, edges, faces, loop=False): | |||
| verts, edges, faces = pydata_from_bmesh(bm) | |||
| bm.free() | |||
| return verts, edges, faces | |||
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| def calc_center_mass_bmesh(center_mode, vertices_I, edges_I, faces_I, mass_of_vertices_I=[1], density_I=[1], skip_test_volume_are_closed=False, quad_mode="BEAUTY", ngon_mode="BEAUTY"): | |||
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In python, it's bad idea to use potentially mutable values as default values for arguments. Basically you have to do def calc_center_mass_bmesh(mass_of_vertices_I = None), and then if mass_of_vertices_I is None: mass_of_vertices = [1].
Also, why _I ?
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Fix [1] to None.
_I - I use it in “for” before. It show all data connect to one object (I-th object).
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when you read this method, you shouldn't have to remember that it is called in a loop :) In another place it can be called without a loop. So, while _I names are okay in context of loop, as names of method parameter this does not make sense, imho.
- rename names of params in library function
satabol
deleted the
fix_5091_Add_a_Node_center_of_mass_for_a_one_or_multiple_meshes
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fix #5091
file for tests:
center_of_mass_t1.v003.blend.zip