# Normals/roughness appear to be missing from display using vtkOBJImporter

**URL:** https://discourse.vtk.org/t/normals-roughness-appear-to-be-missing-from-display-using-vtkobjimporter/12955
**Category:** Support
**Created:** [December 21, 2023, 9:31pm UTC](https://discourse.vtk.org/t/normals-roughness-appear-to-be-missing-from-display-using-vtkobjimporter/12955 "2023-12-21T21:31:55Z")
**Posts on this page:** 4
**Page:** 1

<div class="post-metadata">

### Author: ![scotsman60](https://discourse.vtk.org/user_avatar/discourse.vtk.org/scotsman60/32/6000_2.png) [@scotsman60](https://discourse.vtk.org/u/scotsman60)
#### Post date: [December 21, 2023, 9:31pm UTC](https://discourse.vtk.org/t/normals-roughness-appear-to-be-missing-from-display-using-vtkobjimporter/12955/1 "2023-12-21T21:31:55Z")

</div>

Hello,

I’m using vtkOBJImporter to display an obj file. I have an associated .mtl file which references various roughness, normals, diffuse texture .pngs etc.

VTK succesfully displays the .obj file and I can clearly see the contents of the diffuse texture are included but it seems like the normals and roughness are not being processed - the image is completely flat.

I’m using Python and VTK 9.2.2 on Windows and the code I’m using is shown below.

Any ideas on why the normals/roughness are not being processed?

Thanks in advance,

Doug

```auto
def main():

    # Get the full pathname of the vtp file containing the cow definition from the res folder
    current_file_path = os.path.dirname(os.path.realpath( __file__ ))

    objfname=os.path.join(os.path.dirname(current_file_path), r'res\snowman\snowman_finish.obj')
    matfname=os.path.join(os.path.dirname(current_file_path), r'res\snowman\snowman_finish.mtl')
    texturepath=os.path.join(os.path.dirname(current_file_path), r"res\snowman")

    # Set up the importer and initialize with the files
    objimporter=vtkOBJImporter()
    objimporter.SetFileName(objfname)
    objimporter.SetFileNameMTL(matfname)
    objimporter.SetTexturePath(texturepath)

    # Render window, renderer and interactor
    renderer=vtkRenderer() 
    renwin=vtkRenderWindow()
    renwin.AddRenderer(renderer)
    iren = vtkRenderWindowInteractor()
    iren.SetRenderWindow(renwin)

    # Connect the importer to the render window
    objimporter.SetRenderWindow(renwin)
    objimporter.Update()

    # Render
    iren.Initialize()
    renwin.Render()
    iren.Start()

if __name__ ==' __main__':
    main()

```

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<div class="post-metadata">

### Author: ![scotsman60](https://discourse.vtk.org/user_avatar/discourse.vtk.org/scotsman60/32/6000_2.png) [@scotsman60](https://discourse.vtk.org/u/scotsman60)
#### Post date: [December 21, 2023, 9:33pm UTC](https://discourse.vtk.org/t/normals-roughness-appear-to-be-missing-from-display-using-vtkobjimporter/12955/2 "2023-12-21T21:33:56Z")

</div>

Here’s what the display looks like in VTK

 ![Flat snowman](https://discourse.vtk.org/uploads/default/original/2X/a/a2e9ba80c93733d8f3f8201352f016115efd2b47.png)

And how it looks in an alternate viewer

 ![image](https://discourse.vtk.org/uploads/default/original/2X/f/ff496462662b75af324974a91663f7b3f0464caa.jpeg)

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<div class="post-metadata">

### Author: ![scotsman60](https://discourse.vtk.org/user_avatar/discourse.vtk.org/scotsman60/32/6000_2.png) [@scotsman60](https://discourse.vtk.org/u/scotsman60)
#### Post date: [December 21, 2023, 9:34pm UTC](https://discourse.vtk.org/t/normals-roughness-appear-to-be-missing-from-display-using-vtkobjimporter/12955/3 "2023-12-21T21:34:55Z")

</div>

mtl file

```auto
newmtl snow
Ns 225.000000
Ka 1.000000 1.000000 1.000000
Kd 0.800000 0.800000 0.800000
Ks 0.500000 0.500000 0.500000
Ke 0.000000 0.000000 0.000000
Ni 1.450000
d 1.000000
illum 2
map_Bump -bm 0.500000 snowman2_normal.png
map_Kd snowman2_diffuse.png
map_Ns snowman2_roughness.png

newmtl snowman1.001
Ns 225.000000
Ka 1.000000 1.000000 1.000000
Kd 0.800000 0.800000 0.800000
Ks 0.500000 0.500000 0.500000
Ke 0.000000 0.000000 0.000000
Ni 1.450000
d 1.000000
illum 2
map_Bump -bm 0.500000 snowman1_normal.png
map_Kd snowman1_diffuse.png
map_Ns snowman1_roughness.png

```

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<div class="post-metadata">

### Author: ![scotsman60](https://discourse.vtk.org/user_avatar/discourse.vtk.org/scotsman60/32/6000_2.png) [@scotsman60](https://discourse.vtk.org/u/scotsman60)
#### Post date: [December 23, 2023, 7:22am UTC](https://discourse.vtk.org/t/normals-roughness-appear-to-be-missing-from-display-using-vtkobjimporter/12955/4 "2023-12-23T07:22:17Z")

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OK - After some more research, I found,

1. vtkOBJImporter is known to support only a single texture. Not sure how I missed that i my initial research
2. Even if it supported multiple textures my current approach would not have worked because the default Gouraud shading model only supports a single color texture. I need to update my code to use PBR rendering to see the effects of the different roughness etc, textures.