Color attributes in sculpt mode not showing in instance objects #101150

New Issue

Tonatiuh de San Julián · 2022-09-17T16:24:42+02:00

2022-09-17 16:24:42 +02:00

System Information
Operating system: Linux-5.15.0-47-generic-x86_64-with-glibc2.35 64 Bits
Graphics card: GeForce GTX 670MX/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 418.226.00

Blender Version
Broken: version: 3.4.0 Alpha, branch: master, commit date: 2022-09-16 20:05, hash: e108d67635
Worked: (newest version of Blender that worked as expected)

Short description of error
When sculpting an object its instance reflect the changes after the stroke, but not with color attributes, you have to go out of sculpt mode to see the color attributes.

Exact steps for others to reproduce the error

Open a new sculpt file.
Make and instance in object mode with Alt D
Enter sculpt mode of the original object.
Paint some color attributes
Sculpt with clay brush to see the expected behavior.

Grabación de pantalla desde 17-09-22 16:08:53.webm

One funny thing is that if you give the original object a mirror modifier, the changes to the instance are in real-time, not after the stroke, both for sculpt and for paint. But not when you sculpt or paint in the one without the modifier.

Grabación de pantalla desde 17-09-22 16:22:16.webm

**System Information** Operating system: Linux-5.15.0-47-generic-x86_64-with-glibc2.35 64 Bits Graphics card: GeForce GTX 670MX/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 418.226.00 **Blender Version** Broken: version: 3.4.0 Alpha, branch: master, commit date: 2022-09-16 20:05, hash: `e108d67635` Worked: (newest version of Blender that worked as expected) **Short description of error** When sculpting an object its instance reflect the changes after the stroke, but not with color attributes, you have to go out of sculpt mode to see the color attributes. **Exact steps for others to reproduce the error** 1. Open a new sculpt file. 2. Make and instance in object mode with Alt D 3. Enter sculpt mode of the original object. 4. Paint some color attributes 5. Sculpt with clay brush to see the expected behavior. [Grabación de pantalla desde 17-09-22 16:08:53.webm](https://archive.blender.org/developer/F13504156/Grabación_de_pantalla_desde_17-09-22_16_08_53.webm) One funny thing is that if you give the original object a mirror modifier, the changes to the instance are in real-time, not after the stroke, both for sculpt and for paint. But not when you sculpt or paint in the one without the modifier. [Grabación de pantalla desde 17-09-22 16:22:16.webm](https://archive.blender.org/developer/F13504162/Grabación_de_pantalla_desde_17-09-22_16_22_16.webm)

Tonatiuh de San Julián commented

2022-09-17 16:24:42 +02:00

Added subscriber: @TonatiuhdeSanJulian

Tonatiuh de San Julián commented

2022-09-17 16:31:07 +02:00

Just to clarify I don't think that the expected behavior is real-time, because it start lagging a lot with HighPoly objects, The prefer behavior for me is to actualize the instance or the mirror object immediately after the stroke, like normal sculpt with instances, that way there is no lag while sculpting, only in the visual representation, but just wile the stroke is action.

Tonatiuh de San Julián commented

2022-09-17 16:38:49 +02:00

I just discover that the smear brush and the color filters works as expected, see the video:

Grabación de pantalla desde 17-09-22 16:36:56.webm

I just discover that the smear brush and the color filters works as expected, see the video: [Grabación de pantalla desde 17-09-22 16:36:56.webm](https://archive.blender.org/developer/F13504193/Grabación_de_pantalla_desde_17-09-22_16_36_56.webm)

Julien Kaspar commented

2022-09-19 12:25:45 +02:00

Added subscribers: @JosephEagar, @JulienKaspar

Julien Kaspar commented

2022-09-19 12:25:45 +02:00

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

Julien Kaspar commented

2022-09-19 12:25:45 +02:00

I can confirm this bug.
This seems to be the case ever since the feature was released in 3.2.
@JosephEagar Can you take a look at this?

The ideal behaviour here would be that after each stroke, the instanced obejcts will update, even with modifiers.
But addressing the real time updates when modifiers are involved are likely a general issue in sculpt mode. This would likely be tackeld separately.

I can confirm this bug. This seems to be the case ever since the feature was released in 3.2. @JosephEagar Can you take a look at this? The ideal behaviour here would be that after each stroke, the instanced obejcts will update, even with modifiers. But addressing the real time updates when modifiers are involved are likely a general issue in sculpt mode. This would likely be tackeld separately.

Joseph Eagar commented

2022-10-15 00:10:44 +02:00

After several hours of debugging, I fixed the crashes this situation can cause but, alas, I don't think I can fix the inconsistency in behavior. Whether the update happens in real time or after the stroke (or at all) is surprisingly complicated.

For example, dupli instances (e.g. instancing through collections) update in real time. But not data instances (alt-D). Unless the original object has a modifier, is not multires and is not in Dyntopo mode. Then it will be realtime. If Dyntopo is enabled dupli instances will still be updated, but data ones will not.

After several hours of debugging, I fixed the crashes this situation can cause but, alas, I don't think I can fix the inconsistency in behavior. Whether the update happens in real time or after the stroke (or at all) is surprisingly complicated. For example, dupli instances (e.g. instancing through collections) update in real time. But not data instances (alt-D). Unless the original object has a modifier, is not multires and is not in Dyntopo mode. Then it will be realtime. If Dyntopo is enabled dupli instances will still be updated, but data ones will not.

Tonatiuh de San Julián commented

2022-10-16 14:13:17 +02:00

@JosephEagar the most problematic is the mirror or the array modifier been real-time, because it makes sculpt mode really slow with Highres meshes. And of course changes not showing at all.

Julien Kaspar commented

2022-10-16 16:07:20 +02:00

As the title states, it makes sense to focus in this report on the following bug: Objects with linked object data do not update after a painting stroke.
The moment a regular sculpting operation or stroke is executed, the objects do update though. So this is not a severe issue.

Other issues, like that instances or objects with modifiers are updating in realtime and causing slow performance seems to be much more of a known issue that has been in Blender for many years. It's unrelated to this bug.
It's ok if this is too complex to fix for now. There are multiple issues like this. about a lack of support for sculpt mode with modifiers.

As the title states, it makes sense to focus in this report on the following bug: **Objects with linked object data do not update after a painting stroke.** The moment a regular sculpting operation or stroke is executed, the objects do update though. So this is not a severe issue. Other issues, like that instances or objects with modifiers are updating in realtime and causing slow performance seems to be much more of a known issue that has been in Blender for many years. It's unrelated to this bug. It's ok if this is too complex to fix for now. There are multiple issues like this. about a lack of support for sculpt mode with modifiers.

Joseph Eagar commented

2022-10-16 22:35:19 +02:00

We can't do anything about the array modifier. Mirror modifiers are another matter though we don't have time for it at the moment (there are a number of things we need to fix with how sculpt mode works with mirror modifiers).

Joseph Eagar commented

2022-10-16 22:39:30 +02:00

Anyway, the inconsistency in behavior has to do with what GPU meshes happen to be compatible with what the draw manager wants. If the fast internal sculpt draw mesh happens to be compatible with what the draw manger wants for an instance it will use it, otherwise it will use a normal draw mesh generated from the base mesh.

Philipp Oeser removed the

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Color attributes in sculpt mode not showing in instance objects #101150