Stacked UV faces don't display the normals properly when one set of stacked faces has been rotated 180 degrees. #42965

New Issue

Jerry Dechant · 2014-12-19T23:35:08+01:00

Jerry Dechant commented

2014-12-19 23:35:08 +01:00

System Information
Operating system and graphics card Win 7 64bit, home premium version

Blender Version
Broken: (example: 2.72b Hash: 9e963ae

Worked: (optional)

Short description of error

When I stack UV unwrapped faces in the UV editor,then rotate 180 degrees, or mirror vertically and horizontally in the UV editor. This causes the rotated and/or mirrored UV faces not to display the normals properly.

Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps

create mesh cube,
divide cube vertically down the front center.
mark seams then unwrap.
open UV Image Editor window.
reorient appropriate faces so they are stacked upon each other (front left and right stacked on top of rear left and right.)
select right front and rear UV faces
Mirror the selected faces horizontally and then vertically.
Export UV map.
Use image program to create texture.
Import UV map into image editor to use as guide for texture placement.
Apply desired texture to the image,
save file as tga file with Diffuse designation in the file name.
create and save normals map using CrazyBump (or other program) based upon diffuse map.
load diffuse map into texture "image" area designating mapping coordinates to be UV
load normals map into texture "image" area designating mapping coordinates to be UV
display applied textures to the mesh in the object/edit window.
notice the right side faces (front and back) do not display properly.

NOTE: If this isn't a bug, please direct me to where I can find instructions on how to do this and have the normals appear properly for all faces.

bugReport.blend

bugReport.blend1

BugReportExample_n.tga

BugReportExample_s.tga

BugReportExample_c.tga

**System Information** Operating system and graphics card Win 7 64bit, home premium version **Blender Version** Broken: (example: 2.72b Hash: 9e963ae Worked: (optional) **Short description of error** When I stack UV unwrapped faces in the UV editor,then rotate 180 degrees, or mirror vertically and horizontally in the UV editor. This causes the rotated and/or mirrored UV faces not to display the normals properly. **Exact steps for others to reproduce the error** Based on a (as simple as possible) attached .blend file with minimum amount of steps create mesh cube, divide cube vertically down the front center. mark seams then unwrap. open UV Image Editor window. reorient appropriate faces so they are stacked upon each other (front left and right stacked on top of rear left and right.) select right front and rear UV faces Mirror the selected faces horizontally and then vertically. Export UV map. Use image program to create texture. Import UV map into image editor to use as guide for texture placement. Apply desired texture to the image, save file as tga file with Diffuse designation in the file name. create and save normals map using CrazyBump (or other program) based upon diffuse map. load diffuse map into texture "image" area designating mapping coordinates to be UV load normals map into texture "image" area designating mapping coordinates to be UV display applied textures to the mesh in the object/edit window. notice the right side faces (front and back) do not display properly. NOTE: If this isn't a bug, please direct me to where I can find instructions on how to do this and have the normals appear properly for all faces.![BugReportExample_UV.png](https://archive.blender.org/developer/F132938/BugReportExample_UV.png) [bugReport.blend](https://archive.blender.org/developer/F132939/bugReport.blend) [bugReport.blend1](https://archive.blender.org/developer/F132940/bugReport.blend1) [BugReportExample_n.tga](https://archive.blender.org/developer/F132942/BugReportExample_n.tga) [BugReportExample_s.tga](https://archive.blender.org/developer/F132943/BugReportExample_s.tga) ![BugReportExample_uv_filled.xcf](https://archive.blender.org/developer/F132944/BugReportExample_uv_filled.xcf) [BugReportExample_c.tga](https://archive.blender.org/developer/F132945/BugReportExample_c.tga)

Jerry Dechant commented

2014-12-19 23:35:09 +01:00

Changed status to: 'Open'

Jerry Dechant commented

2014-12-19 23:35:09 +01:00

Added subscriber: @JeromeDechant

Joel Godin commented

2014-12-21 05:40:02 +01:00

Added subscriber: @FloridaJo

Joel Godin commented

2014-12-21 05:40:02 +01:00

I can't follow your steps. I create line down middle front, unwrap and I get this. After that I'm lost. Can you be more specific?
Thanks.

I can't follow your steps. I create line down middle front, unwrap and I get this. After that I'm lost. Can you be more specific? Thanks. ![Screenshot_of_Blender_(12-20-14,_11:38:17_PM).png](https://archive.blender.org/developer/F133027/Screenshot_of_Blender__12-20-14__11_38_17_PM_.png)

Jerry Dechant commented

2014-12-21 09:35:07 +01:00

Actually, if you look at the picture I provided, you can see that I made the box thinner from the side view, that's why the UV Unwrapped and stacked image looks like a large vertical rectangle with smaller rectangle boxes on the top, right side and bottom. You can mark the seams to make it unwrap like that, even if you don't make it thinner from the side. I provided files so you could see what I did. I suggest you use them.

By the way, my step by step instructions are not every little thing you should do, if you know how to use Blender, you should be able to fill in the parts I didn't write down in the instructions.

Actually, if you look at the picture I provided, you can see that I made the box thinner from the side view, that's why the UV Unwrapped and stacked image looks like a large vertical rectangle with smaller rectangle boxes on the top, right side and bottom. You can mark the seams to make it unwrap like that, even if you don't make it thinner from the side. I provided files so you could see what I did. I suggest you use them. By the way, my step by step instructions are not every little thing you should do, if you know how to use Blender, you should be able to fill in the parts I didn't write down in the instructions.

Sergey Sharybin commented

2014-12-26 12:14:34 +01:00

Changed status from 'Open' to: 'Archived'

Sergey Sharybin closed this issue

2014-12-26 12:14:34 +01:00

Sergey Sharybin self-assigned this 2014-12-26 12:14:34 +01:00

Sergey Sharybin commented

2014-12-26 12:14:34 +01:00

Your normal is in tangent space which depends on the UV coordinates. This means rotating UV face would indeed affect on how normals are being calculated. This isn't a bug it's just how tangent spaced normal maps works.

For your particular application you need either:

Bake normals in tangent maps for both faces
Use object space normal map
Use displacement (heights) map

Thanks for the report, but it's not a bug o closing it.

Your normal is in tangent space which depends on the UV coordinates. This means rotating UV face would indeed affect on how normals are being calculated. This isn't a bug it's just how tangent spaced normal maps works. For your particular application you need either: - Bake normals in tangent maps for both faces - Use object space normal map - Use displacement (heights) map Thanks for the report, but it's not a bug o closing it.

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Stacked UV faces don't display the normals properly when one set of stacked faces has been rotated 180 degrees. #42965