Maniphest T74587

Text Extrude with Negative Bevel Shading Issues
Closed, Archived
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Assigned To
None
Authored By
Jeroen Bakker (jbakker)
Mar 9 2020, 8:46 PM
Tags
  • BF Blender
  • Modeling
  • Papercut
Subscribers
Campbell Barton (campbellbarton)
Evan Wilson (EAW)
Hans Goudey (HooglyBoogly)
Jeroen Bakker (jbakker)

Description

System Information
Operating system: Linux-5.0.0-38-generic-x86_64-with-debian-buster-sid 64 Bits
Graphics card: Mesa DRI Intel(R) UHD Graphics 620 (Kabylake GT2) Intel Open Source Technology Center 4.5 (Core Profile) Mesa 19.2.0-devel (git-2631fd3 2019-07-24 cosmic-oibaf-ppa)

Blender Version
Broken: version: 2.83 (sub 7), branch: master, commit date: 2020-03-09 hash: rB503d5c0c652dbce9dad428ab4b19e021c0ca8a39
Worked: version: 2.82

Short description of error
When using an extruded text object with a negative bevel the shading is off.

Exact steps for others to reproduce the error

text-negative-bevel-normals.blend623 KBDownload

  • Open the attached file in Blender 2.82 and 2.83 and see the differences. I expect that half of the extrude Half of the extrude uses wrong data?
  • By changing the bevel depth to positive the shading is correct.

From default blender

  • Create a text
  • set the extrude to a positive number (0.1)
  • set the bevel depth to a negative number (-0.01)

My first impression is that the negative depth was not tested as it has a soft limit in the UI. But it was supported.

Related Objects

Mentioned Here
T71200: Beveled curves geometry contains duplicate vertices
rBe34d3e32dda7: Fix T71200: Build curve geometry in one piece

Event Timeline

Jeroen Bakker (jbakker) created this task.Mar 9 2020, 8:46 PM
Evan Wilson (EAW) changed the task status from Needs Triage to Confirmed.Mar 9 2020, 10:39 PM
Evan Wilson (EAW) added a project: Modeling.
Evan Wilson (EAW) added a subscriber: Evan Wilson (EAW).

I can confirm.

2.83.7

2.82 release

Evan Wilson (EAW) added a subscriber: Hans Goudey (HooglyBoogly).May 2 2020, 9:29 AM

Git bisect points to rBe34d3e32dda7 Fix T71200: Build curve geometry in one piece @Hans Goudey (HooglyBoogly)

Hans Goudey (HooglyBoogly) added a comment.May 2 2020, 11:26 PM

I suspect this is just a downside of using one piece of geometry for the sides of the text. Before each quarter and each side was a separate disconnected piece of geometry, effectively with split normals on the borders between them. Now they're the same mesh, so the shading is incorrectly trying to figure out the weird geometry.

Maybe this could be solved by reverting to the old behavior for negative bevel offsets. Or more deeply by using split normals in this situation if that's possible. I'm not sure what the use case for such geometry is though..

Jeroen Bakker (jbakker) added a comment.May 2 2020, 11:39 PM

We used it for creating distance text with some additional contrast on the edges. I used that as I had sometime pressure finishing a project.

Hans Goudey (HooglyBoogly) added a comment.May 13 2020, 7:23 PM

@Jeroen Bakker (jbakker)
What would be a good resolution of this task in your opinion? I don't think I would classify this as a bug, rather a side effect of creating the curve geometry in one piece.

Campbell Barton (campbellbarton) changed the subtype of this task from "Report" to "To Do".Sep 8 2020, 11:04 AM
Campbell Barton (campbellbarton) added a project: Papercut.
Hans Goudey (HooglyBoogly) added a subscriber: Campbell Barton (campbellbarton).Sep 9 2020, 3:34 AM

@Campbell Barton (campbellbarton) What's the idea with making this a todo? It's not clear if there is anything to do from the report, the change is just a side effect of having a contiguous mesh for the entire section of the curve.

Anyway, custom profile bevels on curves will make it easy to get a pronounced edge.

I would suggest closing this report instead of keeping it cluttering the module page.

Campbell Barton (campbellbarton) moved this task from Backlog to Papercuts on the Modeling board.Sep 21 2020, 1:34 PM
Campbell Barton (campbellbarton) closed this task as Archived.Mar 10 2021, 2:21 PM

@Hans Goudey (HooglyBoogly), it looked like an error, however even after converting to a mesh, these normals remain the same.

As you say, this is just the result of sharing geometry, closing.

Campbell Barton (campbellbarton) changed the subtype of this task from "To Do" to "Report".Mar 10 2021, 2:23 PM