Maniphest T80253

Cylinder smooth shading issue
Closed, Archived
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Assigned To
Germano Cavalcante (mano-wii)
Authored By
Mykhailo (Sunset_Tesnus)
Aug 30 2020, 4:29 PM
Tags
  • BF Blender
Subscribers
Germano Cavalcante (mano-wii)
Marcin Twarowski (Tvaroog)
Mykhailo (Sunset_Tesnus)
Pratik Borhade (PratikPB2123)
tempdevnova (tempdevnova)

Description

System Information
Operating system: Windows-10-10.0.17763-SP0 64 Bits
Graphics card: GeForce RTX 2060 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 451.48

Blender Version
Broken: version: 2.90.0 Beta, branch: master, commit date: 2020-08-25 16:00, hash: rB21cb6f09ffa8
Worked: none

Short description of error
Incorrect shading cone-like cylinder

Exact steps for others to reproduce the error
Create a cylinder
Turn on smooth shading
Mark sharp top and bottom circles or Turn on auto smooth
Scale down one circle

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

Cylinder_smooth_shading_issue.blend2 MBDownload

Related Objects

Event Timeline

Mykhailo (Sunset_Tesnus) created this task.Aug 30 2020, 4:29 PM
Mykhailo (Sunset_Tesnus) updated the task description.Aug 30 2020, 6:24 PM
Mykhailo (Sunset_Tesnus) updated the task description.
Marcin Twarowski (Tvaroog) added a subscriber: Marcin Twarowski (Tvaroog).EditedAug 30 2020, 6:29 PM

It has always looked like this:
How it looks in 2:79


2.83.5

If you want smoother shading you need more polygons:

Germano Cavalcante (mano-wii) closed this task as Archived.Sep 1 2020, 11:02 PM
Germano Cavalcante (mano-wii) claimed this task.
Germano Cavalcante (mano-wii) added a subscriber: Germano Cavalcante (mano-wii).

This is a limitation of OpenGL, whose interpolation is done over triangles.
And in some cases of ngon tessellation, one triangle is smaller than the other.

This same problem is seen in many graphics applications and not just Blender.

Germano Cavalcante (mano-wii) mentioned this in T96061: UV tangents not seamless.Mar 1 2022, 7:16 PM
Germano Cavalcante (mano-wii) merged a task: T96061: UV tangents not seamless.
Germano Cavalcante (mano-wii) added subscribers: tempdevnova (tempdevnova), Pratik Borhade (PratikPB2123).