Spline IK joint_bindings parameter is broken #83164

New Issue

Joseph Brandenburg · 2020-11-28T21:55:40+01:00

2020-11-28 21:55:40 +01:00

First-time contributor

System Information
Operating system: Linux-5.4.0-48-generic-x86_64-with-debian-bullseye-sid 64 Bits
Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 450.80.02

Blender Version
Broken: version: 2.92.0 Alpha, branch: master
Worked: (Seems to work in 2.79, is broken in 2.90.1. I assume 2.80 is where it broke)

Short description of error
The Spline IK constraint has a parameter, joint_bindings that tells the constraint where along the curve to place the joints.
However, this parameter is undefined or at least empty until the user applies the pose.
If the user attempts to access the parameter before the pose is applied, there will be an IndexError. (Alternatively, the parameter can be set from Python and it will then behave normally).
If the user makes Blender re-calculate these bindings (by changing the chain_length parameter through the constraint for example), and attempts to assign or read the property by index, there will be a Crash To Desktop.
(I've never heard of anyone using this feature. The manual doesn't even say how; I'm only using it because I am trying to fix a bug in Spline IK and it was useful for testing an idea.)

Exact steps for others to reproduce the error

Open attached file (there is a bone with Spline IK constraint)
Go to python console
Type C.active_pose_bone.constraints- [x].joint_bindings- [x] (Note that the result is an empty tuple - Bug! If you query the first index, there will be an index error).
Apply the pose with Ctrl-A "Apply Pose as Rest Pose".
Attempt to query the property again: C.active_pose_bone.constraints- [x].joint_bindings- [x]. It will produce correct results (in my example, it should be [1.0, 0.0]).
Steps for Crash To Desktop
In the Bone Constraints Panel, change the chain length back and forth.
Attempt to query the property again: C.active_pose_bone.constraints- [x].joint_bindings[0]
(An aside: it would be nice to change this property to be reversed in order, it's annoying to list(reverse(new_bindings)) when setting it!)
Thanks 😃
bug_start.blend

**System Information** Operating system: Linux-5.4.0-48-generic-x86_64-with-debian-bullseye-sid 64 Bits Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 450.80.02 **Blender Version** Broken: version: 2.92.0 Alpha, branch: master Worked: (Seems to work in 2.79, is broken in 2.90.1. I assume 2.80 is where it broke) **Short description of error** The Spline IK constraint has a parameter, `joint_bindings` that tells the constraint where along the curve to place the joints. However, this parameter is undefined or at least empty until the user applies the pose. If the user attempts to access the parameter before the pose is applied, there will be an `IndexError`. (Alternatively, the parameter can be set from Python and it will then behave normally). If the user makes Blender re-calculate these bindings (by changing the chain_length parameter through the constraint for example), and attempts to assign or read the property by index, there will be a Crash To Desktop. (I've never heard of **anyone** using this feature. The manual doesn't even say how; I'm only using it because I am trying to fix a bug in Spline IK and it was useful for testing an idea.) **Exact steps for others to reproduce the error** - Open attached file (there is a bone with Spline IK constraint) - Go to python console - Type `C.active_pose_bone.constraints- [x].joint_bindings- [x]` (Note that the result is an empty tuple - Bug! If you query the first index, there will be an index error). - Apply the pose with `Ctrl`-`A` "Apply Pose as Rest Pose". - Attempt to query the property again: `C.active_pose_bone.constraints- [x].joint_bindings- [x]`. It will produce correct results (in my example, it should be [1.0, 0.0]). **Steps for Crash To Desktop** - In the Bone Constraints Panel, change the `chain length` back and forth. - Attempt to query the property again: `C.active_pose_bone.constraints- [x].joint_bindings[0]` (An aside: it would be nice to change this property to be reversed in order, it's annoying to `list(reverse(new_bindings))` when setting it!) Thanks 😃 [bug_start.blend](https://archive.blender.org/developer/F9402042/bug_start.blend)

Joseph Brandenburg commented

2020-11-28 21:55:40 +01:00

First-time contributor

Added subscriber: @Josephbburg

Germano Cavalcante commented

2020-12-02 15:18:42 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Germano Cavalcante commented

2020-12-02 15:19:08 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2020-12-02 15:19:08 +01:00

Thanks for the report. I can confirm.

Joseph Brandenburg commented

2020-12-02 16:37:15 +01:00

First-time contributor

Thanks for confirming -- I might fix this one in the process of fixing #81704, since I have to touch the joint binding code to fix that one, too. I'll try to remember to poke if it's out of my depth.