bevel loop slide failures #86768

New Issue

MACHIN3 · 2021-03-20T19:04:02+01:00

MACHIN3 commented

2021-03-20 19:04:02 +01:00

System Information
Operating system: Linux-4.15.0-136-generic-x86_64-with-debian-buster-sid 64 Bits
Graphics card: GeForce GTX 1050/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.39

Blender Version
Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: 02948a2cab
Worked: 2.90.1

Short description of error
Loop sliding with the bevel tool, in particular using percent bevels, will often fail, when edges are at more extreme angles.

It can also happen for offset bevels, but in different conditions:

If there is some kind of internal angle threshold used internally, that determines if an edge is used for loop sliding or not, I'd like to see it exposed. Not just for bpy.ops.mesh.bevel but also (and for me more importantly) for bmesh.ops.bevel.

In 2.90.1 this behavior is not present or fails differently, with usually better results.

video demo:
https://www.youtube.com/watch?v=w8Y5m5NTtQQ

blend file:
bevel_loop_slide_failure.blend

edit: adding a second example, this time with the bevel mod

video demo:
https://www.youtube.com/watch?v=yEnnmwsl20w

blend file:
bevel_loop_slide_failure2.blend

Exact steps for others to reproduce the error

open the blend and bevel the edge loops in the 2 objects
alternate between offset and percent bevels and toggle loop slide on/off

**System Information** Operating system: Linux-4.15.0-136-generic-x86_64-with-debian-buster-sid 64 Bits Graphics card: GeForce GTX 1050/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.39 **Blender Version** Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: `02948a2cab` Worked: 2.90.1 **Short description of error** Loop sliding with the bevel tool, in particular using percent bevels, will often fail, when edges are at more extreme angles. ![loop_slide_fail.png](https://archive.blender.org/developer/F9901345/loop_slide_fail.png) It can also happen for offset bevels, but in different conditions: ![loop_slide_fail2.png](https://archive.blender.org/developer/F9901347/loop_slide_fail2.png) If there is some kind of internal angle threshold used internally, that determines if an edge is used for loop sliding or not, I'd like to see it exposed. Not just for `bpy.ops.mesh.bevel` but also (and for me more importantly) for `bmesh.ops.bevel`. In 2.90.1 this behavior is not present or fails differently, with usually better results. video demo: https://www.youtube.com/watch?v=w8Y5m5NTtQQ blend file: [bevel_loop_slide_failure.blend](https://archive.blender.org/developer/F9901350/bevel_loop_slide_failure.blend) **edit:** adding a second example, this time with the bevel mod video demo: https://www.youtube.com/watch?v=yEnnmwsl20w blend file: [bevel_loop_slide_failure2.blend](https://archive.blender.org/developer/F9917825/bevel_loop_slide_failure2.blend) **Exact steps for others to reproduce the error** * open the blend and bevel the edge loops in the 2 objects * alternate between offset and percent bevels and toggle loop slide on/off

MACHIN3 commented

2021-03-20 19:04:02 +01:00

Added subscriber: @MACHIN3

Ted Milker commented

2021-03-21 13:47:40 +01:00

Added subscriber: @Teds

Ted Milker commented

2021-03-21 13:47:40 +01:00

Confirmed in 2.92.0, Windows 10 64bit

MACHIN3 commented

2021-04-02 13:46:56 +02:00

Added subscriber: @howardt

MACHIN3 commented

2021-04-02 13:46:56 +02:00

I've added a second example, this time using the bevel mod.

@howardt Not a 100% sure, but would this be yours to take on?

I've added a second example, this time using the bevel mod. @howardt Not a 100% sure, but would this be yours to take on?

Falk David commented

2021-04-07 14:26:01 +02:00

Added subscriber: @filedescriptor

Falk David commented

2021-04-07 14:26:01 +02:00

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

Falk David commented

2021-04-07 14:26:01 +02:00

I can confirm this on the latest 2.93.0 Alpha, branch: master, commit date: 2021-04-07 05:32, hash: 2fbee4598c.

I can confirm this on the latest 2.93.0 Alpha, branch: master, commit date: 2021-04-07 05:32, hash: `2fbee4598c`.

Howard Trickey commented

2021-04-10 18:55:12 +02:00

There is an angle below which it won't slide along the edge. It is 0.25 radians = 14.3 degrees. The reason for this was, I think, that at that angle, you have to go about 4 times as much along the sliding edge as the width desired (for offset mode), and people complained about "spikes". This seems like a very technical thing to expose in the UI (control over that angle). But since one can turn loop slide off, maybe I should just use a much tinier angle instead of .25 radians. I will investigate whatever bugs caused me to put 0.25 in in the first place and then decide what to do.

MACHIN3 commented

2021-04-10 18:58:12 +02:00

that at that angle, you have to go about 4 times as much along the sliding edge as the width desired

I would be fine with that, not matter the angle. If I want to loop slide along the edges I have placed, then I want to loop slide along them. Ideally, there would be an option to do this, so use loop slide without any cut off angle.

Beyond that, if you look at the first image, where at the right it isn't loop sliding, it still seems like the bevel amount is way too much, as it overshoots a lot. It's as if the amount is still gotten from the angled edge, despite it not beeing used for loop sliding.
It seems to be the same in the video of the bevel mod.

Whatever setting you expose to facilitate this, please make sure to do it in the bmesh bevel op as well. Thank you!

> that at that angle, you have to go about 4 times as much along the sliding edge as the width desired I would be fine with that, not matter the angle. If I want to loop slide along the edges I have placed, then I want to loop slide along them. Ideally, there would be an option to do this, so use loop slide without any cut off angle. Beyond that, if you look at the first image, where at the right it isn't loop sliding, it still seems like the bevel amount is way too much, as it overshoots a lot. It's as if the amount is still gotten from the angled edge, despite it not beeing used for loop sliding. It seems to be the same in the video of the bevel mod. Whatever setting you expose to facilitate this, please make sure to do it in the bmesh bevel op as well. Thank you!

MACHIN3 commented

2021-06-20 16:30:57 +02:00

Just wanted to bump this, as I feel it's a major shortcoming of the bevel tool/mod right now. I hope this will be resolved in 3.0, but would prefer it much earlier.

blender-admin commented

2021-07-25 21:14:37 +02:00

This issue was referenced by 4886ed2863

This issue was referenced by 4886ed28637cbda056980467934d9d7c4190b6e2

Howard Trickey commented

2021-07-25 21:15:08 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Howard Trickey closed this issue

2021-07-25 21:15:08 +02:00

Howard Trickey self-assigned this 2021-07-25 21:15:08 +02:00

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bevel loop slide failures #86768