MPX SMG
Original model and PBR textures by nebula075.
Source: https://sketchfab.com/3d-models/mpx-smg-238fa4b18f1247e99231529f98d11a61
Author: https://sketchfab.com/nebula075
License: Creative Commons Attribution 4.0 International (CC BY 4.0)
https://creativecommons.org/licenses/by/4.0/
Legal code: https://creativecommons.org/licenses/by/4.0/legalcode
Retrieved: 2026-09-12

Adapted for Astra Attack:
- All 7099 original triangles retained in the first-person model.
- Single OBJ mesh split by vertex connectivity into body, magazine (372 triangles)
  and visible bolt (51 triangles), preserving original UVs and normals.
- Length normalized to 0.600 game metres; +Y up, -Z forward; right-hand grip origin.
- Muzzle, grip, sight, optic-mount and ejection attachment nodes added.
- Original metallic/roughness PBR maps used. AO/Roughness/Metallic packed into RGB.
- Original OpenGL normal map used without green inversion; vectors normalized.
- WebP quality 90 base color; lossless WebP normal and ORM after processing.
- View textures: 1024x1024. Static world textures: 512x512. Embedded in GLB.
- World geometry simplified per connected piece, protecting small pieces, then
  combined into one draw. No rig or imported animation.
- Independent magazine/bolt transform controls are project additions.

These adaptations are not supplied or endorsed by the original author or SIG SAUER.
Credit nebula075, link the model and CC BY 4.0, and indicate modifications when
redistributing these assets. Keep this notice with the GLBs.

Gameplay integration (2026-09-12):
- MPX idle/ADS, recoil, bolt cycle, hold-open, magazine reload, equip and grenade
  recovery are procedural animations authored for this project.
- The shared first-person glove/arm rig is by EXUnum, distributed with Jainesh
  Pathak's SCAR-H First-Person (FPS) Animated, CC BY 4.0:
  https://sketchfab.com/3d-models/scar-h-first-person-fps-animated-404b16a45a224163850df34a20391739
  MPX wrist/finger targets and magazine-following poses are project adaptations.
- MPX firing sound reuses the game's areniporgen CC0 recording with playback-rate
  adjustment; it is not an original MPX recording.
  https://freesound.org/people/areniporgen/sounds/702225/
- HUD/kill-feed silhouette is rasterized from this model by scripts/prepare-smg.py.