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miguel_5616
Participant
October 12, 2025
Answered

Normal map decal on certain axis look weird?

  • October 12, 2025
  • 1 reply
  • 204 views

Whilst working on a personal project I had bought a pack of normal map decals for hard surface modeling when I noticed they looked weird on my model!

At first I figured it was maybe a topology or UV issue on my end but after extensive research, and even noticing UV seams in normal view, found out that wasn't the issue nor an issue to begin with.

So I decided to test it on the simplest thing. Blender's Default Cube.

And here's what I found.


On the image you can see 3 faces in the corner of a cube in ortographic view. The one on the left is the Y axis, one on the right is the X axis, and the one on the bottom the Z axis (This view is from the back of the cube)

Normal maps seem to only work/look as intended on the X axis facing surfaces, whilst the other two axis they look weird and have those visible seams, it is especially noticeable in material view with added complexity.

Now this doesn't seem to be consistent, as on my personal project files, normal map decals on X axis facing surfaces still had these very same issues.

Is there something I'm missing? Is it a shader issue, or project file issue?
For context the file is set to OpenGL normals, and the shader setting itself is "PBR - Metallic Roughness Alpha-blend (starter-assets)"

    Correct answer miguel_5616

    UPDATE - I've found out the issue with the normal looking weird was because I was using Warp Projection, switching to Planar Projection fixes the issue!

    Not sure why it does this, but hopefully someone from Adobe can clarify? Will provide sample images

     

    1 reply

    Cyril Dellenbach
    Community Manager
    Cyril DellenbachCommunity Manager
    Community Manager
    October 13, 2025

    Hi Miguel,

     

     

    A normal map works in a Tangent space in your 2D view. In other words, the top to bottom will always be purple-ish and bottom to top green-ish (in DirectX). Therefore, it's not suprising that it doesn't look the same depending on the cube's face, because each face has a different UV shell that is probably oriented differently.

     

    Same thing goes for seams in the normal map. This is the expected behavior from a Normal map and it doesn't mean that there are seams in your final material.

     

    If there are problems with one of your personal project, this is more likely a UV issue than something else.

     

    Best regards,

     

    Cyril Dellenbach (Micro) | QA Support Artist | Adobe
    M
    miguel_5616Author
    Participant
    October 13, 2025

    Good afternoon Cyril!

    Thank you for the response, I did research a bit into Tangent Spaces, but I assume that would be something that occurs on UV seams, correct? - From what I saw that isn't the issue itself, considering the decals are not overlapping with any UV seams.

     

    As you can see in the image I attached in the original post, the seams created on the Z and Y axis are on the decal itself, you can clearly see them in the circles and across the buckle's attachment point as a clear line dividing the colors, and how it impacts the in material view.

    I'm not sure if the issue is due to the angle of the face itself being perfectly perpendicular to the axis and thus it limits the normal map's ability to create a gradient or not. - I did do a test where I tilted the exported model by 45º on the X axis, and I noticed the issue was then gone due on the previously Z axis perpendicular face.

    Is this just a general limitation of normal maps or does it have to do with the way I set up my model, etc?

    I'm happy to provide the project file if necessary!

    M
    miguel_5616AuthorCorrect answer
    Participant
    October 16, 2025

    UPDATE - I've found out the issue with the normal looking weird was because I was using Warp Projection, switching to Planar Projection fixes the issue!

    Not sure why it does this, but hopefully someone from Adobe can clarify? Will provide sample images

     

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