Drivers - Invalid python expression after rendering #74080

New Issue

thierrry kobyleski · 2020-02-21T16:36:48+01:00

thierrry kobyleski commented

2020-02-21 16:36:48 +01:00

System Information
Linux
Nvidia GTX 780

Blender Version
Broken: 2.82
Worked: (optional)

The property "Use for rendering" in View Layer Properties panel can be driven ... until the first render.

Exact steps for others to reproduce the error
#74080.blend

Open .blend file
Scrub timeline, see driver working
Render image
Scrub timeline

Driver no longer works

**System Information** Linux Nvidia GTX 780 **Blender Version** Broken: 2.82 Worked: (optional) The property "Use for rendering" in View Layer Properties panel can be driven ... until the first render. **Exact steps for others to reproduce the error** [#74080.blend](https://archive.blender.org/developer/F8358124/T74080.blend) - Open .blend file - Scrub timeline, see driver working - Render image - Scrub timeline Driver no longer works

thierrry kobyleski commented

2020-02-21 16:36:48 +01:00

Added subscriber: @thierrykobyleski

Richard Antalik commented

2020-02-21 17:12:11 +01:00

Added subscriber: @iss

Richard Antalik commented

2020-02-21 17:12:11 +01:00

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

Richard Antalik closed this issue

2020-02-21 17:12:11 +01:00

Richard Antalik self-assigned this 2020-02-21 17:12:11 +01:00

Richard Antalik commented

2020-02-21 17:12:11 +01:00

There was error in system console:

Dependency cycle detected:
  SCScene/Parameters Component/PARAMETERS_EVAL() depends on
  SCScene/Parameters Component/DRIVER(view_layers["Cube"].use) via 'Driver -> Driven Property'
  SCScene/Parameters Component/PARAMETERS_EVAL() via 'RNA Target -> Driver'
Detected 1 dependency cycles

Use this driver expression:
int(frame)%2==0

There was error in system console: ``` Dependency cycle detected: SCScene/Parameters Component/PARAMETERS_EVAL() depends on SCScene/Parameters Component/DRIVER(view_layers["Cube"].use) via 'Driver -> Driven Property' SCScene/Parameters Component/PARAMETERS_EVAL() via 'RNA Target -> Driver' Detected 1 dependency cycles ``` Use this driver expression: `int(frame)%2==0`

Richard Antalik changed title from ~~Driving property "Use for rendering" in View Layer Properties panel fails after first render~~ to Drivers - Invalid python expression after rendering

2020-02-21 17:28:14 +01:00

Richard Antalik commented

2020-02-21 17:28:14 +01:00

Changed status from 'Archived' to: 'Confirmed'

Richard Antalik reopened this issue

2020-02-21 17:28:14 +01:00

Richard Antalik removed their assignment 2020-02-27 14:48:15 +01:00

Jacques Lucke commented

2020-03-18 16:57:04 +01:00

Added subscribers: @Sergey, @JacquesLucke

Jacques Lucke commented

2020-03-18 16:57:04 +01:00

I get a different error in this file.

WARN (bke.anim_sys): /home/jacques/blender-git/blender/source/blender/blenkernel/intern/anim_sys.c:1726 BKE_animsys_store_rna_setting: Animato: Invalid path. ID = 'Scene',  'view_layers["Cube"].use[0]'
ERROR (bke.anim_sys): /home/jacques/blender-git/blender/source/blender/blenkernel/intern/anim_sys.c:4190 BKE_animsys_eval_driver: invalid driver - view_layers["Cube"].use[0]

After some investigation, the issue seems to be that during rendering the scene being rendered contains only one view layer; only the one that is rendered currently. Now, some code tries to find the Cube view layer due to the driver while the Sphere view layer is rendered, but does not find it for the reason mentioned above. This produces the invalid driver error. Unfortunately, I don't really understand how all of that fits together..

I tend to call this a known issue for now. @Sergey, what do you think?

I get a different error in this file. ``` WARN (bke.anim_sys): /home/jacques/blender-git/blender/source/blender/blenkernel/intern/anim_sys.c:1726 BKE_animsys_store_rna_setting: Animato: Invalid path. ID = 'Scene', 'view_layers["Cube"].use[0]' ERROR (bke.anim_sys): /home/jacques/blender-git/blender/source/blender/blenkernel/intern/anim_sys.c:4190 BKE_animsys_eval_driver: invalid driver - view_layers["Cube"].use[0] ``` After some investigation, the issue seems to be that during rendering the scene being rendered contains only one view layer; only the one that is rendered currently. Now, some code tries to find the `Cube` view layer due to the driver while the `Sphere` view layer is rendered, but does not find it for the reason mentioned above. This produces the `invalid driver` error. Unfortunately, I don't really understand how all of that fits together.. I tend to call this a known issue for now. @Sergey, what do you think?

Sergey Sharybin commented

2020-03-18 17:30:44 +01:00

@JacquesLucke, dependency graph always consists from a single view layer (no matter if it's render-only or viewport).

What's supposed to happen is all dependencies is what's used in the view layer are supposed to be pulled into the dependency graph. This means that when dependency graph builds Sphere is should see "aha, you need Cube for the driver. Lemme pull it into the dependency graph for you!"

There are tricky parts like how to detect whether ID is needed or not. Currently its based on driver variables IDs. As in, if there is an RNA path in the driver expression which references ID which is not in any of the variables then dependency graph will not see it.

So if the ID is referenced from variable "it should just work". It it's something more tricky like that then it's a known issue. Dependency graph can not parse python code to know used IDs. And there is simple workaround: add dependency as variable.

Hope it all makes sense :)

@JacquesLucke, dependency graph always consists from a single view layer (no matter if it's render-only or viewport). What's supposed to happen is all dependencies is what's used in the view layer are supposed to be pulled into the dependency graph. This means that when dependency graph builds `Sphere` is should see "aha, you need Cube for the driver. Lemme pull it into the dependency graph for you!" There are tricky parts like how to detect whether ID is needed or not. Currently its based on driver variables IDs. As in, if there is an RNA path in the driver expression which references ID which is not in any of the variables then dependency graph will not see it. So if the ID is referenced from variable "it should just work". It it's something more tricky like that then it's a known issue. Dependency graph can not parse python code to know used IDs. And there is simple workaround: add dependency as variable. Hope it all makes sense :)

Sybren A. Stüvel commented

2020-08-13 14:19:08 +02:00

Added subscriber: @dr.sybren

Sybren A. Stüvel commented

2020-08-13 14:19:08 +02:00

@thierrykobyleski what exactly do you want to achieve by animating the view layer's "use for render" property? The view layer seems to still be used in the compositor on all frames.

It helps us to have some context for the report. Is this an intrinsic issue that blocks an entire studio from working? Some recently introduced problem, where older versions of Blender did this just fine? Or is it just an experiment to see if this could work?

@thierrykobyleski what exactly do you want to achieve by animating the view layer's "use for render" property? The view layer seems to still be used in the compositor on all frames. It helps us to have some context for the report. Is this an intrinsic issue that blocks an entire studio from working? Some recently introduced problem, where older versions of Blender did this just fine? Or is it just an experiment to see if this could work?

Sybren A. Stüvel commented

2020-08-20 14:12:56 +02:00

Changed status from 'Confirmed' to: 'Needs User Info'

Sybren A. Stüvel commented

2020-09-07 11:00:49 +02:00

Changed status from 'Needs User Info' to: 'Archived'

Sybren A. Stüvel closed this issue

2020-09-07 11:00:49 +02:00

Sybren A. Stüvel self-assigned this 2020-09-07 11:00:49 +02:00

Sybren A. Stüvel commented

2020-09-07 11:00:49 +02:00

No activity for more than a week. As per the tracker policy we assume the issue is gone and can be closed.

Thanks again for the report. If the problem persists please open a new report with the required information.

No activity for more than a week. As per the tracker policy we assume the issue is gone and can be closed. Thanks again for the report. If the problem persists please open a new report with the required information.

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Drivers - Invalid python expression after rendering #74080