Normal/Bump map doesn't work properly in Sandbox

[Alec]

I’m exporting in .glb from Blender to the Sandbox, but one of the Normal Map doesn’t work on a specific mesh. Instead of displacing the bumps, if I increase the Bump strength in the LEVELS section of the material, it’s like it deforms the normals of the mesh.
The normals of the mesh are fine, and the normal map works fine as well in Blender.

Here the blend file and the .glb I’m using in the Sandbox:

https://mega.nz/file/W4USjJ7Y#1TtcZptfj2bBIA2TvYU1eyo8s1WbOCBVE9U113gV0jc

You can see the problem in the Grunge2 material (just slide up and down the Bump strenght).

If I apply the same texture as a bump map to the wall material it works fine.

[Deltakosh]

Pinging @Drigax

[Drigax]

Investigating now…

@Alec I’m not sure what I’m supposed to be seeing…

In blender, I assigned the albedo, normal and roughness textures to the brick material, and can see it appears when rendered as:

likewise the imported glb also renders as:

Can you be as specific as possible as to what is wrong? Please use as many examples, playgrounds and images as possible to describe your issue.

[Alec]

You are seeing the mesh backwards.

What I get in Blender:

The normal map of the bricks material is working fine, the bumps of the bricks are there.

What i get on Sandbox:

The brick mesh is totally flat, no bump from the normal map, and if I increase the strenght of the bump I only get (what I think is) a visual glitch:

To immediately see the error go to the sandbox, select the Grunge2 material, then in the Inspector scroll down in the LEVELS section, now slide the Bump Strenght up and down. Instead of seeing the bump on the mesh you only get a visual glitch:

[Vinc3r]

It looks like come from the glTF exporter, which probably fail to convert tif (not a web format) to png/jpg.

When using tif in Blender, we see issues in normal map colorimetry:

After converting tif to png and use it in Blender, normal map is now… normal :

[Alec]

Yeah, I was using the automatic conversion in blender to convert .tiff to .jpg when exporting in .glb.
Manually converting the maps in photoshop solves the problem! Thank you!

Do you recommend to convert all the textures in .png outside blender or it’s just the normal map that get this kind of errors?

[Vinc3r]

I think it’s better to use assets already web-compatible, it eases the workflow.

For mass-converting images, I use XnConvert (also merged in XnViewMP, that I use too).