GPencil obdata used by more than one object makes depgraph eval extremely slow (affects e.g. liboverrides) #95735

New Issue

Nick Alberelli · 2022-02-12T18:57:05+01:00

Nick Alberelli commented

2022-02-12 18:57:05 +01:00

System Information
Operating system: Linux-5.15.5-76051505-generic-x86_64-with-glibc2.31 64 Bits
Graphics card: NVIDIA GeForce RTX 3090/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.86

Tested Blender Versions
Broken: version: 3.0.1, branch: master, commit date: 2022-01-25 17:19, hash: dc2d180181
Broken: version: 3.1.0 Beta, branch: master, commit date: 2022-02-11 22:52, hash: 27d3140b13
Broken: version: 3.2.0 Alpha, branch: master, commit date: 2022-02-11 22:58, hash: 35c261dfcf
Broken: version: 3.2.0 Alpha, branch: greasepencil-object, commit date: 2022-02-02 08:51, hash: c876bccb57

Short description of error
When using library override with a collection that contains a lattice and a grease pencil object there is a considerable frame rate slowdown.

Library Override Playback
local example.mp4

Expected Result
linked example.mp4

Long description of error
When rigging any grease pencil to a lattice and deforming the lattice in some way yields very good playback speeds. If a collection containing these elements (A grease pencil deformed by a lattice) the collection can be linked to no extra frame rate cost. But when using a library override there is a considerable change in frame rate.

Exact steps for others to reproduce the error from startup file

Create a grease pencil object.
Deform the object with a lattice modifier
Open a new blend file and link the collection.
Compare the linked frame rate to the frame rate when using library override.

Exact steps for others to reproduce the error from example .blend

Open "heavy_test_file.blend" and note frame rate.
Compare to "test file with library override.blend"
Open a new blend file and link the collection.
Compare the linked frame rate to the frame rate when using library override.

Example Blends: GP Library Override Lattice Issue.zip

**System Information** Operating system: Linux-5.15.5-76051505-generic-x86_64-with-glibc2.31 64 Bits Graphics card: NVIDIA GeForce RTX 3090/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.86 **Tested Blender Versions** Broken: version: 3.0.1, branch: master, commit date: 2022-01-25 17:19, hash: `dc2d180181` Broken: version: 3.1.0 Beta, branch: master, commit date: 2022-02-11 22:52, hash: `27d3140b13` Broken: version: 3.2.0 Alpha, branch: master, commit date: 2022-02-11 22:58, hash: `35c261dfcf` Broken: version: 3.2.0 Alpha, branch: greasepencil-object, commit date: 2022-02-02 08:51, hash: `c876bccb57` **Short description of error** When using library override with a collection that contains a lattice and a grease pencil object there is a considerable frame rate slowdown. **Library Override Playback** [local example.mp4](https://archive.blender.org/developer/F12863960/local_example.mp4) **Expected Result** [linked example.mp4](https://archive.blender.org/developer/F12863961/linked_example.mp4) **Long description of error** When rigging any grease pencil to a lattice and deforming the lattice in some way yields very good playback speeds. If a collection containing these elements (A grease pencil deformed by a lattice) the collection can be linked to no extra frame rate cost. But when using a library override there is a considerable change in frame rate. **Exact steps for others to reproduce the error from startup file** 1. Create a grease pencil object. 2. Deform the object with a lattice modifier 3. Open a new blend file and link the collection. 4. Compare the linked frame rate to the frame rate when using library override. **Exact steps for others to reproduce the error from example .blend** 1. Open "heavy_test_file.blend" and note frame rate. 2. Compare to "test file with library override.blend" 3. Open a new blend file and link the collection. 4. Compare the linked frame rate to the frame rate when using library override. Example Blends: [GP Library Override Lattice Issue.zip](https://archive.blender.org/developer/F12863963/GP_Library_Override_Lattice_Issue.zip)

Nick Alberelli commented

2022-02-12 18:57:05 +01:00

Added subscriber: @TinyNick

Pratik Borhade commented

2022-02-14 04:47:08 +01:00

Added subscriber: @PratikPB2123

Pratik Borhade commented

2022-02-14 04:47:08 +01:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Pratik Borhade commented

2022-02-14 04:47:08 +01:00

Thanks for the report. Can notice reasonable drop in fps with your provided file.
Reports on performance are usually not considered as bug reports (unless they are regression).

To improve performance, consider using less complex geometry, simpler shaders and smaller textures.```

I will let developers decide.

(2.83 is oldest version I checked and same problem I noticed there)

Thanks for the report. Can notice reasonable drop in fps with your provided file. Reports on performance are usually not considered as bug reports (unless they are regression). ```Thanks for the report. While we do continue to work on improving performance in general, potential performance improvements are not handled as bug reports. To improve performance, consider using less complex geometry, simpler shaders and smaller textures.``` I will let developers decide. (2.83 is oldest version I checked and same problem I noticed there)

Nick Alberelli commented

2022-02-14 14:13:16 +01:00

Thank you, just some additional context: lattices are often used when rigging grease pencil characters, smaller grease pencil objects dont seem to produce this error (needs testing). I only discovered this because the addition of a new more detailed character unexpectedly tanked my performance.

And this only happens with linking, one can copy and paste the character without a loss in framerate. Meaning this effectively breaks rigged gp characters from being linked across scenes.

Thank you, just some additional context: lattices are often used when rigging grease pencil characters, smaller grease pencil objects dont seem to produce this error (needs testing). I only discovered this because the addition of a new more detailed character unexpectedly tanked my performance. And this only happens with linking, one can copy and paste the character without a loss in framerate. Meaning this effectively breaks rigged gp characters from being linked across scenes.

Bastien Montagne commented

2022-02-14 15:41:08 +01:00

Added subscriber: @mont29

Bastien Montagne commented

2022-02-14 15:41:08 +01:00

I would let #dependency_graph team check on this first...

From a quick investigation, liboverrides are basically ten times slower to evaluate than either fully linked data, or fully local data:

Type of data/file	`BKE_object_handle_data_update` on `OBLattice`	`BKE_object_eval_uber_data` on `OBGP_Pirate.002`	Total eval time
Linked	~004ms	~004ms	~009ms
Linked, made local	~004ms	~004ms	~009ms
liboverride	~050ms	~050ms	~100ms

Further investigation: issue comes from the fact that the greasepencil obdata (Pirata.003) is used by two objects in liboverride case (it has two ID users, the linked object and its local override). Issue being, when evaluated GP ID has more than one user, it is fully duplicated, otherwise it is evaluated 'in place' (BKE_gpencil_prepare_eval_data)?

Copying a GP data takes a lot of time.

I think this is a depsgraph/GPencil issue really.

@TinyNick temporary workaround is to also make the GP obdata itself a liboverride (from the Outliner e.g.).

I would let #dependency_graph team check on this first... From a quick investigation, liboverrides are basically ten times slower to evaluate than either fully linked data, or fully local data: | Type of data/file | `BKE_object_handle_data_update` on `OBLattice` | `BKE_object_eval_uber_data` on `OBGP_Pirate.002` | Total eval time | | ---- | ---- | ---- | ---- | | Linked | ~004ms | ~004ms | ~009ms | | Linked, made local | ~004ms | ~004ms | ~009ms | | liboverride | ~050ms | ~050ms | ~100ms | ------------------------- Further investigation: issue comes from the fact that the greasepencil obdata (`Pirata.003`) is used by *two* objects in liboverride case (it has two ID users, the linked object and its local override). Issue being, when evaluated GP ID has more than one user, it is fully duplicated, otherwise it is evaluated 'in place' (`BKE_gpencil_prepare_eval_data`)? Copying a GP data takes *a lot* of time. I think this is a depsgraph/GPencil issue really. --------------------------- @TinyNick temporary workaround is to also make the GP obdata itself a liboverride (from the Outliner e.g.).

Bastien Montagne changed title from ~~Library Overides: Low Framerate when using Grease Pencil + Lattice Modifier~~ to GPencil obdata used by more than one object makes depgraph eval extremely slow (affects e.g. liboverrides)

2022-02-14 15:41:50 +01:00

Nick Alberelli commented

2022-02-17 18:49:06 +01:00

@mont29 Thank you, that does appear to work as a temporary workaround. I appreciate the tip it seems to have worked! The playback speed is reasonable using the workaround.