Geometry Nodes 'Bounding Box' Doesn't Update #118507

New Issue

Brady Johnston · 2024-02-20T14:33:58+01:00

Brady Johnston commented

2024-02-20 14:33:58 +01:00

System Information
Operating system: Windows-10-10.0.22000-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3090/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 551.52

Blender Version
Broken: version: 4.0.2, branch: blender-v4.0-release, commit date: 2023-12-05 07:41, hash: 9be62e85b727
Tested also in 4.2 Alpha in which it is also broken

Short description of error
When updating meshes via the python API, the Bounding Box node doesn't update despite the mesh updating and seemingly all other geometry nodes updating.

Exact steps for others to reproduce the error

As a reproducible example, you can create a mesh made of some random vertices. On each frame change, the mesh positions are scaled.

import bpy
from bpy.app.handlers import persistent
import numpy as np

# create a mesh made of some random points
points = np.random.rand(500, 3)
mesh = bpy.data.meshes.new('test')
mesh.from_pydata(vertices=points, edges=[], faces=[])
obj = bpy.data.objects.new('test', mesh)
bpy.data.collections['Collection'].objects.link(obj)

@persistent
def _update_points():
    def update_scene(scene):
        # get the mesh to be updated
        obj = bpy.data.objects['test']
        
        # init an array for the values, store the position values in it
        arr = np.zeros(500 * 3, dtype=float)
        obj.data.attributes['position'].data.foreach_get('vector', arr)
        
        # scale the positions by some amount, then set the new positions to these scaled
        # values and update the data so everything in Blender updates
        arr = arr * 1.01
        obj.data.attributes['position'].data.foreach_set('vector', arr.copy(order='c'))
        obj.data.update()
        
    return update_scene

# append this update function to the frame change handler
bpy.app.handlers.frame_change_post.append(_update_points())

With this mesh now scaling, add a Geometry Nodes modifier. From what I have tested, all of the nodes work up the updated mesh, except for the Bounding Box node, which doesn't register the updated mesh, except when changing into and out of edit mode.

You can temporarily get the Bounding Box node to register the updated mesh, by first putting a Separate Geometry node before it and having some non-zero selection, then the Bounding Box will work on the updated mesh. If you remove the node however, it works then on the original mesh again.

**System Information** Operating system: Windows-10-10.0.22000-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3090/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 551.52 **Blender Version** Broken: version: 4.0.2, branch: blender-v4.0-release, commit date: 2023-12-05 07:41, hash: `9be62e85b727` Tested also in 4.2 Alpha in which it is also broken **Short description of error** When updating meshes via the python API, the `Bounding Box` node doesn't update despite the mesh updating and seemingly all other geometry nodes updating. **Exact steps for others to reproduce the error** As a reproducible example, you can create a mesh made of some random vertices. On each frame change, the mesh positions are scaled. ```python import bpy from bpy.app.handlers import persistent import numpy as np # create a mesh made of some random points points = np.random.rand(500, 3) mesh = bpy.data.meshes.new('test') mesh.from_pydata(vertices=points, edges=[], faces=[]) obj = bpy.data.objects.new('test', mesh) bpy.data.collections['Collection'].objects.link(obj) @persistent def _update_points(): def update_scene(scene): # get the mesh to be updated obj = bpy.data.objects['test'] # init an array for the values, store the position values in it arr = np.zeros(500 * 3, dtype=float) obj.data.attributes['position'].data.foreach_get('vector', arr) # scale the positions by some amount, then set the new positions to these scaled # values and update the data so everything in Blender updates arr = arr * 1.01 obj.data.attributes['position'].data.foreach_set('vector', arr.copy(order='c')) obj.data.update() return update_scene # append this update function to the frame change handler bpy.app.handlers.frame_change_post.append(_update_points()) ``` With this mesh now scaling, add a Geometry Nodes modifier. From what I have tested, all of the nodes work up the updated mesh, except for the `Bounding Box` node, which doesn't register the updated mesh, except when changing into and out of edit mode. You can _temporarily_ get the `Bounding Box` node to register the updated mesh, by first putting a `Separate Geometry` node before it and having some _non-zero_ selection, then the `Bounding Box` will work on the updated mesh. If you remove the node however, it works then on the original mesh again.

blender_Lnz89Cofd7.mp4

2.6 MiB

example_scaling_bug.blend

936 KiB

Brady Johnston added the

labels 2024-02-20 14:33:58 +01:00

Jacques Lucke commented

2024-02-20 15:03:05 +01:00

Didn't test it yet, but may be a missing update tag when using attribute.foreach_set vs. setting vertex.co manually (which calls rna_Mesh_update_positions_tag).
Maybe try setting on of the vertex positions manually after foreach_set.

Didn't test it yet, but may be a missing update tag when using `attribute.foreach_set` vs. setting `vertex.co` manually (which calls `rna_Mesh_update_positions_tag`). Maybe try setting on of the vertex positions manually after `foreach_set`.

Brady Johnston commented

2024-02-20 16:02:30 +01:00

You are correct. If I change it to the code below and manually update each vertex then the bounding box node works.

        arr = arr * 1.01
        arr = arr.reshape((500, 3))
        for i, vert in enumerate(obj.data.vertices):
            vert.co = arr[i, :]
        obj.data.update()

You are correct. If I change it to the code below and manually update each vertex then the bounding box node works. ```python arr = arr * 1.01 arr = arr.reshape((500, 3)) for i, vert in enumerate(obj.data.vertices): vert.co = arr[i, :] obj.data.update() ```

Jacques Lucke commented

2024-02-20 17:12:15 +01:00

Not a fix yet, but it's likely also enough to only set a single vertex' position instead of all of them.

Germano Cavalcante added

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Geometry Nodes 'Bounding Box' Doesn't Update #118507