Artifacts when Exporting Scenes with Objects Hidden from Viewport

[Xaldew]

Describe the bug
Hello!

I've noticed that attempting to export scenes which contains objects that have
hide_viewport == True yields some strange looking artifacts when re-imported
(see screenshots below).

I'm currently working around this by having a small export script that
essentially does this:

for obj in bpy.data.objects:
    if obj.hide_viewport:
        obj.hide_viewport = False
bpy.ops.export_scene.gltf(filepath=f'{output}.gltf',
                          export_cameras=True,
                          export_lights=True,
                          export_format='GLTF_SEPARATE')

This works, but for large scenes (e.g., San Miguel from issue #2101) this can take
a full day to complete.

To Reproduce
Steps to reproduce the behavior:

1. Open included "arcsphere-50.blend" file.
2. Export the scene to glb or glTF.
3. Open a new instance of Blender
4. Import the previously exported scene.

Expected behavior
The exported scene should match the "arsphere_expected.glb" file.
(i.e., all objects, including the ones marked with hide_viewport = True,
should be included, and at their correct position).

Screenshots
Scene with the artifact, presumably from the "hidden" instances:

Scene exported with no objects with hide_viewport == True.

.blend file/ .gltf (mandatory)
The zipped file includes a .blend file with half of all objects/instances "hidden" with hide_viewport = True,
as well as a zip with the expected export result and the received result.
arcsphere-50.zip

Version

• OS: Linux
• Blender Versions 3.6, 4.0

[julienduroure]

Confirmed.
Investigation in progress. (and I will try to get a small file that show this issue, as this one is not very easy to handle for debugging)

[Xaldew]

Ah yes sorry, I should really have done that from the beginning. Here's a much simpler .blend + .glb file that still exhibits this issue:
instances.zip

[julienduroure]

Hello,
Problem comes from object that are hidden in viewport have not the real world matrix stored. Because they are hidden in viewport, matrix is not set.
I will push a PR in a few minutes, where I do the following: For these objects, I un-hide them, update the depsgraph, get the matrix, and hide again. Not sure about impact on performance, but this is the only way to get the right matrices