bpy.app.driver_namespace: no way to properly initialize for driver in material #109720

New Issue

Ilja Razinkov · 2023-07-05T03:15:58+02:00

Ilja Razinkov commented

2023-07-05 03:15:58 +02:00

System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2060 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 531.79

Blender Version
Broken: version: 3.6.0, branch: blender-v3.6-release, commit date: 2023-06-27 08:08, hash: c7fc78b81ecb
Worked: version: 3.5.1, branch: blender-v3.5-release, commit date: 2023-04-24 18:11, hash: e1ccd9d4a1, type: release

Caused by 46be42f6b1

Short description of error
I have material with "value" node driven by driver. driver calls custom function from bpy.app.driver_namespace. bpy.app.driver_namespace populated with function in pre/post loading handler. Despite of that there is no function at load and initial render with that material gives wrong result. This worked well in 3.5.0

Exact steps for others to reproduce the error

in Blender 3.6.0 open attached handle_driver_problem360.blend
execute code in text block. This script adds pre/post loading handler. Both handlers add "dn_test" function to bpy.app.driver_namespace. this function used in material "value" node, with expression "dn_test(depsgraph)"
reload the file. since handlers are installed, dn_test function should be added to namespace BEFORE evaluating driver in material, and material should have proper value upon opening (1.0). But this does not happen, upon loading the value is "0.0" and in console can be seen the reason:

Error in PyDriver: expression failed: dn_test(depsgraph)
For target: (type=NodeTree, name="Shader Nodetree", property=default_value, property_index=-1)

Traceback (most recent call last):
  File "<bpy driver>", line 1, in <module>
NameError: name 'dn_test' is not defined

switch to "cycles" render mode, observe the objects are red (incorrect)
Click on "value" node to update driver. at this time dn_test perfectly found and value updates to 1.0. Observe objects turn to green in viewport
Repeat the same steps in Blender 3.5.1. Observer that after reload at step 3) "value" node have proper value 1.0 right from the start, and there is no errors in console

**System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 2060 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 531.79 **Blender Version** Broken: version: 3.6.0, branch: blender-v3.6-release, commit date: 2023-06-27 08:08, hash: `c7fc78b81ecb` Worked: version: 3.5.1, branch: blender-v3.5-release, commit date: 2023-04-24 18:11, hash: e1ccd9d4a1d3, type: release Caused by 46be42f6b16314f59a37ebb430d77d12e7a88461 **Short description of error** I have material with "value" node driven by driver. driver calls custom function from bpy.app.driver_namespace. bpy.app.driver_namespace populated with function in pre/post loading handler. Despite of that there is no function at load and initial render with that material gives wrong result. This worked well in 3.5.0 **Exact steps for others to reproduce the error** 1) in Blender 3.6.0 open attached handle_driver_problem360.blend 2) execute code in text block. This script adds pre/post loading handler. Both handlers add "dn_test" function to bpy.app.driver_namespace. this function used in material "value" node, with expression "dn_test(depsgraph)" 3) reload the file. since handlers are installed, dn_test function should be added to namespace BEFORE evaluating driver in material, and material should have proper value upon opening (1.0). But this does not happen, upon loading the value is "0.0" and in console can be seen the reason: ``` Error in PyDriver: expression failed: dn_test(depsgraph) For target: (type=NodeTree, name="Shader Nodetree", property=default_value, property_index=-1) Traceback (most recent call last): File "<bpy driver>", line 1, in <module> NameError: name 'dn_test' is not defined ``` 4) switch to "cycles" render mode, observe the objects are red (incorrect) 5) Click on "value" node to update driver. at this time dn_test perfectly found and value updates to 1.0. Observe objects turn to green in viewport 6) Repeat the same steps in Blender 3.5.1. Observer that after reload at step 3) "value" node have proper value 1.0 right from the start, and there is no errors in console

handle_driver_problem360.blend

966 KiB

2023-07-05_04-13-36.png

660 KiB

Ilja Razinkov added the

labels 2023-07-05 03:15:58 +02:00

YimingWu commented

2023-07-05 04:38:10 +02:00

From here 4.0, 3.6, 3.5.1 at e1ccd9d4a1 and 3.5.0 at cf82e5fe57 seems to be all broken, needs to click on the value for it to become green. Auto execution is on. I'm on linux.

Not sure if this is a intended use.

Here's what I have for output, this is just opening the file:

Error in PyDriver: expression failed: dn_test(depsgraph)
For target: (type=NodeTree, name="Shader Nodetree", property=default_value, property_index=-1)

name 'dn_test' is not defined

Traceback (most recent call last):
  File "<bpy driver>", line 1, in <module>
NameError: name 'dn_test' is not defined

Then click run script (nothing outputs, as expected), then File -> Revert:

Read blend: /home/yiming/Downloads/handle_driver_problem360.blend
Load Handler (PRE): /home/yiming/Downloads/handle_driver_problem360.blend None

Error in PyDriver: expression failed: dn_test(depsgraph)
For target: (type=NodeTree, name="Shader Nodetree", property=default_value, property_index=-1)

name 'dn_test' is not defined

Traceback (most recent call last):
  File "<bpy driver>", line 1, in <module>
NameError: name 'dn_test' is not defined
Load Handler (POST): /home/yiming/Downloads/handle_driver_problem360.blend None

From here 4.0, 3.6, 3.5.1 at e1ccd9d4a1 and 3.5.0 at cf82e5fe57c4 seems to be _all_ broken, needs to click on the value for it to become green. Auto execution is on. I'm on linux. Not sure if this is a intended use. Here's what I have for output, this is just opening the file: ``` Error in PyDriver: expression failed: dn_test(depsgraph) For target: (type=NodeTree, name="Shader Nodetree", property=default_value, property_index=-1) name 'dn_test' is not defined Traceback (most recent call last): File "<bpy driver>", line 1, in <module> NameError: name 'dn_test' is not defined ``` Then click run script (nothing outputs, as expected), then `File -> Revert`: ``` Read blend: /home/yiming/Downloads/handle_driver_problem360.blend Load Handler (PRE): /home/yiming/Downloads/handle_driver_problem360.blend None Error in PyDriver: expression failed: dn_test(depsgraph) For target: (type=NodeTree, name="Shader Nodetree", property=default_value, property_index=-1) name 'dn_test' is not defined Traceback (most recent call last): File "<bpy driver>", line 1, in <module> NameError: name 'dn_test' is not defined Load Handler (POST): /home/yiming/Downloads/handle_driver_problem360.blend None ```

YimingWu added the

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

bpy.app.driver_namespace: no way to properly initialize for driver in material #109720