Drivers with custom python functions are broken #68213

New Issue

Marco · 2019-08-04T10:26:36+02:00

Marco commented

2019-08-04 10:26:36 +02:00

System Information
Operating system: Windows-10-10.0.17134 64 Bits
Graphics card: GeForce GTX 1060 3GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.64

Blender Version
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: f6cb5f5449

Short description of error
This was a problem in 2.79 too, so I guess it's not high priority, but I just wanted to put it here since i couldn't find it on the site.
Basically if you write a custom function in Python that controls the value of some properties on other objects, and then use it in the expression field of a driver, those properties update in the Properties panel, but not in the viewport, and old ways of manually updating the driver have no effect now (see attached .blend file for more details).

A very short term and janky solution could be to make the "Update dependancies" accessible from Python

Exact steps for others to reproduce the error

Just open the .blend file and run the script in the Text editor. I wrote 2 methods to control properties trough driver function but none of them work (the driver with the custom function is on propHolder.rotation_euler[0])

bug driver update.blend

**System Information** Operating system: Windows-10-10.0.17134 64 Bits Graphics card: GeForce GTX 1060 3GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.64 **Blender Version** Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: `f6cb5f5449` **Short description of error** This was a problem in 2.79 too, so I guess it's not high priority, but I just wanted to put it here since i couldn't find it on the site. Basically if you write a custom function in Python that controls the value of some properties on other objects, and then use it in the expression field of a driver, those properties update in the Properties panel, but not in the viewport, and old ways of manually updating the driver have no effect now (see attached .blend file for more details). A very short term and janky solution could be to make the "Update dependancies" accessible from Python **Exact steps for others to reproduce the error** Just open the .blend file and run the script in the Text editor. I wrote 2 methods to control properties trough driver function but none of them work (the driver with the custom function is on propHolder.rotation_euler[0]) [bug driver update.blend](https://archive.blender.org/developer/F7648452/bug_driver_update.blend)

Marco commented

2019-08-04 10:26:36 +02:00

Added subscriber: @Tareyes

Marcin Surma commented

2019-12-18 19:30:47 +01:00

Added subscriber: @WWS3D

Marcin Surma commented

2019-12-18 19:30:47 +01:00

{F8232639}yes im try to use drivers to move object by key frames value... and update do not work... It was working on 2.79 when I turn on trusted expresion... or something like that... but now I can't turn it on right now becouse not shows up.

{[F8232639](https://archive.blender.org/developer/F8232639/driver_bug.blend)}yes im try to use drivers to move object by key frames value... and update do not work... It was working on 2.79 when I turn on trusted expresion... or something like that... but now I can't turn it on right now becouse not shows up.

Richard Antalik commented

2020-01-07 12:52:24 +01:00

Added subscriber: @iss

Richard Antalik commented

2020-01-07 12:52:24 +01:00

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

Richard Antalik closed this issue

2020-01-07 12:52:24 +01:00

Richard Antalik self-assigned this 2020-01-07 12:52:24 +01:00

Richard Antalik commented

2020-01-07 12:52:24 +01:00

@Tareyes from your blend file it seems that you are using drivers "backwards". I am no expert in this regard, in fact I had to follow manual on how this is supposed to work

When I follow https://docs.blender.org/manual/en/latest/animation/drivers/workflow_examples.html#custom-function-square-value, I have no issues.

@Tareyes from your blend file it seems that you are using drivers "backwards". I am no expert in this regard, in fact I had to follow manual on how this is supposed to work When I follow https://docs.blender.org/manual/en/latest/animation/drivers/workflow_examples.html#custom-function-square-value, I have no issues.

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Drivers with custom python functions are broken #68213