Grease Pencil: Crash weight painting on stroke with generative modifier [subdivide] - also generative modifiers create actual editable points? #78884

New Issue

Sergey Kulnevsky · 2020-07-13T15:32:04+02:00

Sergey Kulnevsky commented

2020-07-13 15:32:04 +02:00

System Information
Operating system: Windows-10-10.0.16299-SP0 64 Bits
Graphics card: Intel(R) HD Graphics 530 Intel 4.5.0 - Build 22.20.16.4836

Blender Version
Broken: version: 2.83.2, branch: master, commit date: 2020-07-09 05:50, hash: 239fbf7d93

Short description of error
Blender crashes when you are trying draw weight on subdevided grease pensil object (does not seem to happen on the regular meshes).

Exact steps for others to reproduce the error
0. Open attachment.

Try to draw weight on grease pencil object.
CrashGreasePenscilArmatureSubdivide.blend

What I have done:
create a new grease pencil object (Blank)
In Draw mode make some figure.
In Edit mode make few simplifies.
In Object mode add Subdivide; add armature; set perrent with empty groups
In Weigth paint mode try to draw weigth
Crash.

Sorry. My English not so good. I hope, I have create a good description.

**System Information** Operating system: Windows-10-10.0.16299-SP0 64 Bits Graphics card: Intel(R) HD Graphics 530 Intel 4.5.0 - Build 22.20.16.4836 **Blender Version** Broken: version: 2.83.2, branch: master, commit date: 2020-07-09 05:50, hash: `239fbf7d93` **Short description of error** Blender crashes when you are trying draw weight on subdevided grease pensil object (does not seem to happen on the regular meshes). **Exact steps for others to reproduce the error** 0. Open attachment. 1. Try to draw weight on grease pencil object. [CrashGreasePenscilArmatureSubdivide.blend](https://archive.blender.org/developer/F8691430/CrashGreasePenscilArmatureSubdivide.blend) What I have done: create a new grease pencil object (Blank) In Draw mode make some figure. In Edit mode make few simplifies. In Object mode add Subdivide; add armature; set perrent with empty groups In Weigth paint mode try to draw weigth Crash. Sorry. My English not so good. I hope, I have create a good description.

Sergey Kulnevsky commented

2020-07-13 15:32:04 +02:00

Added subscriber: @dlavsevo

blender-admin commented

2020-07-13 15:32:04 +02:00

#79610 was marked as duplicate of this issue

Richard Antalik commented

2020-07-14 23:32:35 +02:00

Added subscriber: @iss

Richard Antalik commented

2020-07-14 23:32:35 +02:00

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

Richard Antalik commented

2020-07-14 23:32:35 +02:00

Crash wasn't immediate, but not really problem to reproduce.

Exception thrown: read access violation. dw was 0xFFFFFFFFFFFFFFFF.

>	blender.exe!BKE_defvert_find_index(const MDeformVert * dvert, const int defgroup) Line 675	C

 	blender.exe!BKE_defvert_ensure_index(MDeformVert * dvert, const int defgroup) Line 702	C
 	blender.exe!brush_draw_apply(tGP_BrushWeightpaintData * gso, bGPDstroke * gps, int pt_index, const int radius, const int * co) Line 261	C
 	blender.exe!gpencil_weightpaint_brush_do_frame(bContext * C, tGP_BrushWeightpaintData * gso, bGPDlayer * gpl, bGPDframe * gpf, const float[4] * diff_mat) Line 548	C
 	blender.exe!gpencil_weightpaint_brush_apply_to_layers(bContext * C, tGP_BrushWeightpaintData * gso) Line 619	C
 	blender.exe!gpencil_weightpaint_brush_apply(bContext * C, wmOperator * op, PointerRNA * itemptr) Line 661	C
 	blender.exe!gpencil_weightpaint_brush_apply_event(bContext * C, wmOperator * op, const wmEvent * event) Line 704	C
 	blender.exe!gpencil_weightpaint_brush_modal(bContext * C, wmOperator * op, const wmEvent * event) Line 781	C
 	blender.exe!wm_handler_operator_call(bContext * C, ListBase * handlers, wmEventHandler * handler_base, wmEvent * event, PointerRNA * properties, const unsigned char * kmi_idname) Line 2018	C
 	blender.exe!wm_handlers_do_intern(bContext * C, wmEvent * event, ListBase * handlers) Line 2806	C
 	blender.exe!wm_handlers_do(bContext * C, wmEvent * event, ListBase * handlers) Line 2854	C
 	blender.exe!wm_event_do_handlers(bContext * C) Line 3283	C
 	blender.exe!WM_main(bContext * C) Line 478	C
 	blender.exe!main(int argc, const unsigned char * * UNUSED_argv_c) Line 534	C

Crash wasn't immediate, but not really problem to reproduce. `Exception thrown: read access violation. dw was 0xFFFFFFFFFFFFFFFF.` ``` > blender.exe!BKE_defvert_find_index(const MDeformVert * dvert, const int defgroup) Line 675 C blender.exe!BKE_defvert_ensure_index(MDeformVert * dvert, const int defgroup) Line 702 C blender.exe!brush_draw_apply(tGP_BrushWeightpaintData * gso, bGPDstroke * gps, int pt_index, const int radius, const int * co) Line 261 C blender.exe!gpencil_weightpaint_brush_do_frame(bContext * C, tGP_BrushWeightpaintData * gso, bGPDlayer * gpl, bGPDframe * gpf, const float[4] * diff_mat) Line 548 C blender.exe!gpencil_weightpaint_brush_apply_to_layers(bContext * C, tGP_BrushWeightpaintData * gso) Line 619 C blender.exe!gpencil_weightpaint_brush_apply(bContext * C, wmOperator * op, PointerRNA * itemptr) Line 661 C blender.exe!gpencil_weightpaint_brush_apply_event(bContext * C, wmOperator * op, const wmEvent * event) Line 704 C blender.exe!gpencil_weightpaint_brush_modal(bContext * C, wmOperator * op, const wmEvent * event) Line 781 C blender.exe!wm_handler_operator_call(bContext * C, ListBase * handlers, wmEventHandler * handler_base, wmEvent * event, PointerRNA * properties, const unsigned char * kmi_idname) Line 2018 C blender.exe!wm_handlers_do_intern(bContext * C, wmEvent * event, ListBase * handlers) Line 2806 C blender.exe!wm_handlers_do(bContext * C, wmEvent * event, ListBase * handlers) Line 2854 C blender.exe!wm_event_do_handlers(bContext * C) Line 3283 C blender.exe!WM_main(bContext * C) Line 478 C blender.exe!main(int argc, const unsigned char * * UNUSED_argv_c) Line 534 C ```

Sergey Kulnevsky commented

2020-07-17 08:58:52 +02:00

so. what I can do with this information? will this mistake resolved at some version of blender? i think this problem is not critical. i do not know, why i have used subdivide.

Richard Antalik commented

2020-07-21 00:57:50 +02:00

In #78884#980740, @dlavsevo wrote:
so. what I can do with this information? will this mistake resolved at some version of blender? i think this problem is not critical. i do not know, why i have used subdivide.

It's for developers to see where crash happened

> In #78884#980740, @dlavsevo wrote: > so. what I can do with this information? will this mistake resolved at some version of blender? i think this problem is not critical. i do not know, why i have used subdivide. It's for developers to see where crash happened

Philipp Oeser commented

2020-07-31 17:43:40 +02:00

Added subscribers: @antoniov, @lichtwerk

Philipp Oeser commented

2020-07-31 17:43:40 +02:00

Armature modifier is not neccessary to show the issue.

Could it be that there is something fundamentaly "wrong" (or at least very different compared to mesh modifiers) with the "show_in_editmode" modifier option with greasepencil and generative modifiers?
For mesh objects, the editmesh control points (vertices) are always the same, even for generative modifiers:

adding geometry (e.g. subdivision modifier) will of course add geometry, but the editcage is the same.
removing geometry (e.g. weld modifier) will of course remove geometry, but the editcage is the same.

For greasepencil the above is not the same:

adding geometry (e.g. subdivide modifier) will of course add to the stroke, but these appears as editable control points (you cannot select them though, you cannot vertex paint on them [no crash here though] etc)
removing geometry (e.g. simplify modifier) will of course remove from the stroke, but then you can only edit remaining control points (select, vertex paint, weight paint), leading to unexpected results when you disable the "show_in_editmode" modifier option again.

So in the case of this report, indices of the deformgroup cannot match, leading to crash.
It is also weird that those generative modifiers do their thing in the deformStroke callbacks, should these be more in the generateStrokes callbacks?
Crash can probably avoided, but to me this sound like it could go wrong in many, many other places.

@antoniov : is this really by design? (dare setting to High prio for clarification)

Armature modifier is not neccessary to show the issue. Could it be that there is something fundamentaly "wrong" (or at least very different compared to mesh modifiers) with the "show_in_editmode" modifier option with greasepencil and generative modifiers? For mesh objects, the editmesh control points (vertices) are always the same, even for generative modifiers: - adding geometry (e.g. subdivision modifier) will of course add geometry, but the editcage is the same. - removing geometry (e.g. weld modifier) will of course remove geometry, but the editcage is the same. For greasepencil the above is not the same: - adding geometry (e.g. subdivide modifier) will of course add to the stroke, but these appears as editable control points (you cannot select them though, you cannot vertex paint on them [no crash here though] etc) - removing geometry (e.g. simplify modifier) will of course remove from the stroke, but then you can only edit remaining control points (select, vertex paint, weight paint), leading to unexpected results when you disable the "show_in_editmode" modifier option again. So in the case of this report, indices of the deformgroup cannot match, leading to crash. It is also weird that those generative modifiers do their thing in the `deformStroke` callbacks, should these be more in the `generateStrokes` callbacks? Crash can probably avoided, but to me this sound like it could go wrong in many, many other places. @antoniov : is this really by design? (dare setting to High prio for clarification)

Philipp Oeser changed title from ~~Crash subdivided Grease Pensil in Weight paint mode~~ to Grease Pencil: Crash weight painting on stroke with generative modifier [subdivide] - also generative modifiers create actual editable points?

2020-07-31 17:46:03 +02:00

Antonio Vazquez commented

2020-07-31 18:02:49 +02:00

The generateStrokes callback is only designed to add new strokes, never to modifiy existing strokes. The simplify or subdivide are using an existing stroke.

I'm going to look at the problem.

The `generateStrokes` callback is only designed to add new strokes, never to modifiy existing strokes. The simplify or subdivide are using an existing stroke. I'm going to look at the problem.

Antonio Vazquez self-assigned this 2020-07-31 18:05:26 +02:00

blender-admin commented

2020-07-31 18:20:27 +02:00

This issue was referenced by 39d7c111db

This issue was referenced by 39d7c111dbed051d5ac29e7f05fb9b346e4f0ce7

blender-admin commented

2020-07-31 18:20:27 +02:00

This issue was referenced by 71683be4bb

This issue was referenced by 71683be4bb6e8bb65844a48b282c3c5662839b1c

Antonio Vazquez commented

2020-07-31 18:21:28 +02:00

Changed status from 'Confirmed' to: 'Resolved'