"Some polygons of Parthurnax not assigned to any body part." error on unmodified model

[XJDHDR]

@niftools/blender-niftools-addon-reviewer -

Before creating a new issue, ensure that

• Read the user documentation.
• Check that the issue hasn't already been reported.
• Read through the list of Helpful resources links on the right-hand side.
• Talk with the developers to ensure its a valid issue

The issue will get closed off immediately as invalid if

• Looking for support where the forums, chat or documentation is more appropriate.
• Goes off topic, loses focus or turns into a discussion.
• Removing parts of the issue template.

Fill out the template below to the best of your ability, including .blend files, nifs, logs; help us to help you.

Issue Overview

I was attempting to modify the model for Paarthurnax (Skyrim LE version, not SE). When I exported my edited model, I encountered the following error:

Some polygons of Parthurnax not assigned to any body part.The unassigned polygons have been selected in the mesh so they can easily be identified.
D:\Users\<username removed>\AppData\Roaming\Blender Foundation\Blender\2.83\scripts\addons\io_scene_niftools\modules\nif_export\geometry\mesh\__init__.py:692

The addon then selected a face (3 vertices) on the model's left wing (please see 2nd screenshot). The problem is that I hadn't touched those vertices or anything on the wing to begin with.

I then tried importing the original model into a new instance of Blender and then just export it without changing anything to see if the original model was working. I had the same error and the addon selected the same 3 vertices. The main question here is whether there is something wrong with the original model itself or is NifTools not importing or exporting it correctly.

Version Information

Blender Niftools Addon Version Info

Niftools Addon version: 0.0.13

Blender Version Info

Blender version: 2.83.5

Platform information

Windows 10 Pro x64 v20.04

Steps to Reproduce

1. Extract a copy of Pathurnax.nif from the Skyrim LE Meshes BSA (Meshes\Actors\Dragon\Character Assets). Or use the attached copy.
2. Import it into Blender. I did not change any of the settings from their default. Or open the attached .blend file.
3. Export model as an NIF. I did not change any of the settings here either.

Expected Result

The unedited model to be exported successfully.

Actual Result

The error noted above appeared, the 3 vertices in question were selected and the NIF was not exported.

Possible Fix

Can't think of anything.

Screenshot

Logs and Files

< No log files were created. >

Info Bar Output

Info bar output.txt

Console Output

< The console was empty>

Blend File

Parthurnax-unmodified.zip

Nif File

parthurnax.zip

Similar Known Issues

There are 2 other issues where the same error message appeared but they've already been fixed and I don't think they have the same cause: #284 and #444

Additional Information

These other dragon models I tried didn't have this problem. They could all be exported to new NIFs without issue:

• Alduin.nif
• BossDragon.nif
• Dragon.nif

I'm also using a PortableApps.com version of Blender downloaded from here, if that makes a difference: https://sourceforge.net/projects/portableapps/files/Blender%20Portable/

[neomonkeus]

Thanks for the issue report, its rare that we get the template filled in completely and correctly.
This really helps with reproducing & troubleshooting.

[XJDHDR]

You're welcome. If there's anything else you need from me, do let me know.

[Candoran2]

Assigning the selected polygons to a body part seems to fix it, but I'll have to see whether it's a problem with the import or the model itself that causes this.

[SubhadeepG]

I checked parthurnax.nif and all vertices are in a body part. That means something is wrong with the import process.