# 'Export Scene' (glTF) not writing surface normals

**URL:** https://discourse.paraview.org/t/export-scene-gltf-not-writing-surface-normals/15192
**Category:** ParaView Support
**Created:** [August 8, 2024, 6:58pm UTC](https://discourse.paraview.org/t/export-scene-gltf-not-writing-surface-normals/15192 "2024-08-08T18:58:23Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![inealey](https://discourse.paraview.org/user_avatar/discourse.paraview.org/inealey/32/16422_2.png) [@inealey](https://discourse.paraview.org/u/inealey)
#### Post date: [August 8, 2024, 6:58pm UTC](https://discourse.paraview.org/t/export-scene-gltf-not-writing-surface-normals/15192/1 "2024-08-08T18:58:24Z")

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Hi ParaViewers,

I’m trying to export `glTF` files representing a polygonal mesh for each time step in a simulation. As far as I can tell, `Export Scene` is the only way to use the glTF writer.

However, it is not writing my `Normals` array required for smooth shading with other graphics libraries.

Desired Appearance:

 ![image](https://discourse.paraview.org/uploads/default/original/2X/6/67b5ddf916a01d160fbe7c8cb48104b2546f4e5b.jpeg)

What I’m getting:

 ![image](https://discourse.paraview.org/uploads/default/original/2X/f/f712ba34e1bb6ce0a21e8f4bb1dcb47787825008.jpeg)

I observe the same behavior using `Export Scene` with `.vtp` format as well, but not when I do `Save Data` as `.obj` or `.ply` (but these are “legacy” exchange formats, I’d really prefer to use glTF)

**Steps to reproduce with `Paraview 5.12.0, Windows 11`:**

1. Download sample red blood cell dataset from Argonne tutorial:

`https://web.cels.anl.gov/projects/alcf_vis_internal/MISC/BLOODFLOW_TUTORIAL_DATA.tar.gz`

1. Load all `.vtp` and `.vtu` time series

2. hide `particles.vtu`

3. Export Scene → choose glTF

4. select `Save Normal` when the dialog box opens:  
 ![gltf_export_dialog](https://discourse.paraview.org/uploads/default/original/2X/b/bda520aba525440c7a85cf8b05ea2d118dd80136.jpeg)

5. open resulting glTF file and observe missing `Normals` array

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### Author: ![nicolas.vuaille](https://discourse.paraview.org/user_avatar/discourse.paraview.org/nicolas.vuaille/32/5873_2.png) [@nicolas.vuaille](https://discourse.paraview.org/u/nicolas.vuaille)
#### Post date: [August 9, 2024, 7:32am UTC](https://discourse.paraview.org/t/export-scene-gltf-not-writing-surface-normals/15192/2 "2024-08-09T07:32:53Z")

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Hi @inealey ,

Thanks for this detailed report! It looks indeed like a limitation of the current implementation.

We have a global ticket about gltf support in ParaView, feel free to comment also there: [https://gitlab.kitware.com/paraview/paraview/-/issues/22446](https://gitlab.kitware.com/paraview/paraview/-/issues/22446)