Grease Pencil Reproject Strokes is incorrectly placing the strokes on the Back Faces when canvas is intersecting the object #88998

New Issue

Sahin Ersoz · 2021-06-09T12:09:11+02:00

Sahin Ersoz commented

2021-06-09 12:09:11 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 457.51

Blender Version
Broken: version: 2.93.0, branch: master, commit date: 2021-06-02 11:21, hash: 84da05a8b8
Worked: (newest version of Blender that worked as expected) Blender 2.92

Short description of error
Grease Pencil Reproject Strokes is incorrectly placing the strokes on the Back Faces when canvas is intersecting the object.

Exact steps for others to reproduce the error

In Blender with the default cube present add a grease pencil object. Leave it in the world center.
Create a layer and a material.
press 1 to go to Front View.
Draw something (while the Canvas is also at the world center and intersecting the Cube).
Switch to Grease Pencil Edit and select all strokes/points.
Under menu item: Grease Pencil / Cleanup / Reproject Strokes.
For Projection Type choose "Surface" (optionally turn on "Keep Original").

This will result in strokes being projected on the back faces of the cube, instead of the front faces.

[Based on the default startup or an attached .blend file (as simple as possible)]
ReprojectStrokes_Bug.blend

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 457.51 **Blender Version** Broken: version: 2.93.0, branch: master, commit date: 2021-06-02 11:21, hash: `84da05a8b8` Worked: (newest version of Blender that worked as expected) Blender 2.92 **Short description of error** Grease Pencil **Reproject Strokes** is incorrectly placing the strokes on the Back Faces when canvas is intersecting the object. **Exact steps for others to reproduce the error** In Blender with the default cube present add a grease pencil object. Leave it in the world center. Create a layer and a material. press 1 to go to Front View. Draw something (while the Canvas is also at the world center and intersecting the Cube). Switch to Grease Pencil Edit and select all strokes/points. Under menu item: Grease Pencil / Cleanup / Reproject Strokes. For Projection Type choose "Surface" (optionally turn on "Keep Original"). This will result in strokes being projected on the back faces of the cube, instead of the front faces. ![GP_Reproject_Strokes_B293_text.jpg](https://archive.blender.org/developer/F10164046/GP_Reproject_Strokes_B293_text.jpg) ![GP_Reproject_Strokes_B292_text.jpg](https://archive.blender.org/developer/F10164045/GP_Reproject_Strokes_B292_text.jpg) [Based on the default startup or an attached .blend file (as simple as possible)] [ReprojectStrokes_Bug.blend](https://archive.blender.org/developer/F10164040/ReprojectStrokes_Bug.blend)

Sahin Ersoz commented

2021-06-09 12:09:11 +02:00

Added subscriber: @sse

Richard Antalik commented

2021-06-09 12:43:39 +02:00

Added subscribers: @antoniov, @iss

Richard Antalik commented

2021-06-09 12:43:39 +02:00

@antoniov is this bug? Manual doesn't specify this and I am not sure from reading the code.

Antonio Vazquez commented

2021-06-09 12:47:17 +02:00

Added subscriber: @mano-wii

Antonio Vazquez commented

2021-06-09 12:47:17 +02:00

GPencil code is just using standard Blender function and I don't know too mucho abut them

Maybe @mano-wii, that fixed a bug in this area lately and he knows better than me how reproject works and can help here.

GPencil code is just using standard Blender function and I don't know too mucho abut them Maybe @mano-wii, that fixed a bug in this area lately and he knows better than me how reproject works and can help here.

blender-admin commented

2021-06-09 14:32:50 +02:00

This issue was referenced by 0cd6c1d502

This issue was referenced by 0cd6c1d502bcec9e41d9d8d9d67f79179ee3c71a

blender-admin commented

2021-06-09 14:32:50 +02:00

This issue was referenced by ea3895558d

This issue was referenced by ea3895558d7b174347d1ba1f03fdb22c90e67a79

Germano Cavalcante commented

2021-06-09 14:34:45 +02:00

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

Germano Cavalcante closed this issue

2021-06-09 14:34:45 +02:00

Germano Cavalcante self-assigned this 2021-06-09 14:34:45 +02:00

Antonio Vazquez commented

2021-06-09 15:43:25 +02:00

Thanks @mano-wii !

Sahin Ersoz commented

2021-06-12 11:43:37 +02:00

Thank you, Antonio and Germano!
Unfortunately the problem still persists in Blender Release Candidate 2.93.1
ReprojectStrokes_Bug2.blend
I attached the Blender scene. Please open it in both 2.92 and 2.93.1. If you Re-project the lines from the Camera's point of view you will see the difference in behavior. The strokes end up on the wrong side with 2.93.1.
Thank you, again for all your hard work!
Sahin

Thank you, Antonio and Germano! Unfortunately the problem still persists in Blender Release Candidate 2.93.1 [ReprojectStrokes_Bug2.blend](https://archive.blender.org/developer/F10168095/ReprojectStrokes_Bug2.blend) I attached the Blender scene. Please open it in both 2.92 and 2.93.1. If you Re-project the lines from the **Camera's point of view** you will see the difference in behavior. The strokes end up on the wrong side with 2.93.1. Thank you, again for all your hard work! Sahin

Pratik Borhade commented

2021-08-23 10:06:03 +02:00

Added subscriber: @PratikPB2123

Pratik Borhade commented

2021-08-23 10:06:03 +02:00

Unfortunately the problem still persists in Blender Release Candidate 2.93.1

Hi, the commit was added in #88449: Blender LTS: Maintenance Task 2.93 after finding the good commit to fix: #89101

You can try again with next 2.93.4 build. Fix added in blender-v2.93-release branch a few minutes before: 0cd6c1d502

>Unfortunately the problem still persists in Blender Release Candidate 2.93.1 Hi, the commit was added in `#88449: Blender LTS: Maintenance Task 2.93` after finding the good commit to fix: #89101 You can try again with next 2.93.4 build. Fix added in `blender-v2.93-release` branch a few minutes before: 0cd6c1d502

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Grease Pencil Reproject Strokes is incorrectly placing the strokes on the Back Faces when canvas is intersecting the object #88998