Child Of Constraint does not allow to set inverse matrix via python API #81949

New Issue

Daniel Salazar · 2020-10-22T09:30:04+02:00

Daniel Salazar commented

2020-10-22 09:30:04 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1080 with Max-Q Design/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71

Short description of error
Can not create a child of constraint and set it's inverse matrix in python due to the automatic execution of inverse matrix calculation introduced by this commit ad70d4b095

Exact steps for others to reproduce the error

ChildOf.blend

Run the included script,
Check the constraint's inverse matrix by running this in the console

C.object.constraints['Child Of'].inverse_matrix

It will give you the following matrix:

Matrix(((1.0, -0.0, 0.0, -0.0),
        (-0.0, 1.0, -0.0, 0.0),
        (0.0, -0.0, 1.0, -0.0),
        (-0.0, 0.0, -0.0, 1.0)))

Which is different than the one the script tried to set:

constraint.inverse_matrix = ((-1.0, -0.0, 0.0, -0.0),
							(-0.0, -1.0, -0.0, 0.0),
							(0.0, -0.0, 1.0, -0.0),
							(-0.0, 0.0, -0.0, 1.0))

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1080 with Max-Q Design/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71 **Short description of error** Can not create a child of constraint and set it's inverse matrix in python due to the automatic execution of inverse matrix calculation introduced by this commit ad70d4b095 **Exact steps for others to reproduce the error** [ChildOf.blend](https://archive.blender.org/developer/F9033179/ChildOf.blend) Run the included script, Check the constraint's inverse matrix by running this in the console ``` C.object.constraints['Child Of'].inverse_matrix ``` It will give you the following matrix: ``` Matrix(((1.0, -0.0, 0.0, -0.0), (-0.0, 1.0, -0.0, 0.0), (0.0, -0.0, 1.0, -0.0), (-0.0, 0.0, -0.0, 1.0))) ``` Which is different than the one the script tried to set: ``` constraint.inverse_matrix = ((-1.0, -0.0, 0.0, -0.0), (-0.0, -1.0, -0.0, 0.0), (0.0, -0.0, 1.0, -0.0), (-0.0, 0.0, -0.0, 1.0)) ```

Daniel Salazar commented

2020-10-22 09:30:05 +02:00

Added subscriber: @zanqdo

blender-admin commented

2020-10-22 09:42:08 +02:00

This issue was referenced by cf8642d9fa

This issue was referenced by cf8642d9fac4cec7d3ee434a5403c2bbc8c5c21c

Campbell Barton commented

2020-10-22 09:48:01 +02:00

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

Campbell Barton closed this issue

2020-10-22 09:48:01 +02:00

Campbell Barton self-assigned this 2020-10-22 09:48:01 +02:00

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Child Of Constraint does not allow to set inverse matrix via python API #81949