Pose Bones BPY BPY bugged #129815

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wueo · 2024-11-04T19:08:48+01:00

wueo commented

2024-11-04 19:08:48 +01:00

System Information
Operating system: Linux-6.11.6-200.fsync.fc40.x86_64-x86_64-with-glibc2.39 64 Bits, X11 UI
Graphics card: NVIDIA GeForce RTX 3080 Ti/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 565.57.01

Blender Version
Broken: version: 4.2.3 LTS, branch: blender-v4.2-release, commit date: 2024-10-14 15:20, hash: 0e22e4fcea03
Worked: (None or no1 that i know of)

Short description of error
hello

trying to move through bpy the pose bones head, head_local, tail, tail_local through python gives error saying :

Error: Python: Traceback (most recent call last):
File "/home/vuaieo/Desktop/BPY Pose Bones codes.blend/Text", line 4, in
AttributeError: bpy_struct: attribute "head" from "Bone" is read-only

the code: bpy.data.objects['Armature'].pose.bones['Bone'].bone.matrix gives 3x3 matrix
not sure if is a bug but the bpy.data.objects['Armature'].pose.bones['Bone'].bone.matrix_local gives 4x4 for the edit bone and not pose bone even if it says its pose bone🥶
and also there is no moving center for the pose bone and the rotation do rotates around the head and not center . usualy when you select a bone(edit) and move or rotate you rotate on center and not heads...

Exact steps for others to reproduce the error
open the blend file and script editor where i prepared the codes to be pasted in the python console to see yourselfs.
and dear gods please make this no feature request again🙏🥴🖖

**System Information** Operating system: Linux-6.11.6-200.fsync.fc40.x86_64-x86_64-with-glibc2.39 64 Bits, X11 UI Graphics card: NVIDIA GeForce RTX 3080 Ti/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 565.57.01 **Blender Version** Broken: version: 4.2.3 LTS, branch: blender-v4.2-release, commit date: 2024-10-14 15:20, hash: `0e22e4fcea03` Worked: (None or no1 that i know of) **Short description of error** hello 1. trying to move through bpy the pose bones head, head_local, tail, tail_local through python gives error saying : Error: Python: Traceback (most recent call last): File "/home/vuaieo/Desktop/BPY Pose Bones codes.blend/Text", line 4, in <module> AttributeError: bpy_struct: attribute "head" from "Bone" is read-only 2. the code: bpy.data.objects['Armature'].pose.bones['Bone'].bone.matrix gives 3x3 matrix not sure if is a bug but the bpy.data.objects['Armature'].pose.bones['Bone'].bone.matrix_local gives 4x4 for the edit bone and not pose bone even if it says its pose bone🥶 3. and also there is no moving center for the pose bone and the rotation do rotates around the head and not center . usualy when you select a bone(edit) and move or rotate you rotate on center and not heads... **Exact steps for others to reproduce the error** open the blend file and script editor where i prepared the codes to be pasted in the python console to see yourselfs. and dear gods please make this no feature request again🙏🥴🖖

BPY Pose Bones codes.blend

1.5 MiB

wueo added the

labels 2024-11-04 19:08:48 +01:00

Germano Cavalcante commented

2024-11-04 20:25:52 +01:00

Hi, as I understand it, the Bone object represents the original bone in its rest position, the PoseBone object is the transformed version for poses, and the EditBone is a temporary object used for editing the original Bone.

It's by design that in Edit Mode, the median center pivot is the average of the selected elements' heads and tails, as both can be transformed in edit mode.

I'm not familiar enough with the details to explain why Bone.matrix is a 3x3 matrix, but this doesn't seem to be a bug.

The head, tail, and center attributes of a Pose Bone are read-only in the Python API, and accessing them should raise an error, which is the behavior you're experiencing.

So overall, I don't think this is a bug report, but rather a misunderstanding of the Python API and Blender's structure.

Hi, as I understand it, the `Bone` object represents the original bone in its rest position, the `PoseBone` object is the transformed version for poses, and the `EditBone` is a temporary object used for editing the original `Bone`. It's by design that in Edit Mode, the median center pivot is the average of the selected elements' heads and tails, as both can be transformed in edit mode. I'm not familiar enough with the details to explain why `Bone.matrix` is a 3x3 matrix, but this doesn't seem to be a bug. The head, tail, and center attributes of a `Pose Bone` are read-only in the Python API, and accessing them should raise an error, which is the behavior you're experiencing. So overall, I don't think this is a bug report, but rather a misunderstanding of the Python API and Blender's structure.

Germano Cavalcante added

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labels 2024-11-04 20:26:22 +01:00

wueo commented

2024-11-05 00:31:26 +01:00

hi thanks for answer but the console said its error. lets say you need to move the pose bone in specific place that the middle of it would be placed there, how you do that withiout beeing math genius scientist if even possible? shouldnt there be command for middle aswell too for simple addon wannabe makers? and matrix 4x4 is from pose bones and not edit bone codes... i not sure what information i can give else for this , please tell more so we can implement these not features asap...

Germano Cavalcante commented

2024-11-05 01:03:20 +01:00

I understand your concern, but calculating the midpoint of a pose bone seems straightforward. If you have the coordinates of the tail and head, the middle point would be calculated simply as (tail + head) * 0.5 or (tail + head) / 2. Therefore, I don't see the need to add a specific API in C++ to calculate this value.

Anyway, thanks for the report. However, please use other channels for user feedback and feature requests: Feature Requests.

For more information on why this isn't considered a bug, please visit: Not a Bug.

I understand your concern, but calculating the midpoint of a pose bone seems straightforward. If you have the coordinates of the tail and head, the middle point would be calculated simply as `(tail + head) * 0.5` or `(tail + head) / 2`. Therefore, I don't see the need to add a specific API in C++ to calculate this value. Anyway, thanks for the report. However, please use other channels for user feedback and feature requests: [Feature Requests](https://developer.blender.org/docs/handbook/communication/user_feedback/#feature-requests). For more information on why this isn't considered a bug, please visit: [Not a Bug](https://developer.blender.org/docs/handbook/bug_reports/not_a_bug/).

Germano Cavalcante closed this issue

2024-11-05 01:03:24 +01:00

Blender Bot added

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and removed

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labels 2024-11-05 01:03:25 +01:00

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