**System Information**
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 980/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 466.27
**Blender Version**
Broken: version: 2.93.0 Beta, branch: master, commit date: 2021-05-08 23:52, hash: `rB3c7b80ae2ca6`
Worked: 2.92.0
---
==Short description of error:==
Extreme Normal editing(like flipping the normal and using other normal editing modifiers) causes flat shading.
{F10074818}
{F10074764}
In the image above,the sphere has a Data Transfer modifier which is receiving the Normals of the plane.
As in the upper image(2.92.0),the sphere is shaded smooth while in the lower image(2.93 beta) it gets flat shading at some faces.
---
==Exact steps for others to reproduce the error==
{icon fa-plus} OS Conditon: **WIN 10** |Blender: **2.93.0 Beta**
- Default scene with default cube deleted.
- Add a sphere object and a plane,add a Data Tansfer modifier to the sphere which transfers the normals of the plane to the sphere.
- Have the sphere some negative Z axis transformation then observe its normal,the flat shading should be appearing at some angle.
{icon bicycle spin} Below is a blend file with the setup above with an additional shading node in the material:
This is the additional node which filps the normals of the geometry:
{F10074849} And the results in the respective versions:
{F10074857}
{F10074859}
{F10074867}