Here are some skyboxes that I created in SpaceEngine that I though I could share with you guys, divided by theme. These skyboxes use VTF version 7.5 and were originally created for CS:GO. However, they do work with GMOD and Source Filmmaker.
Earth-Moon system
- EarthSpace01: Earth from medium Earth orbit (1 skybox)
- EarthSpace02 pack: Earth from the Earth-Moon L5 Lagrange point (3 skyboxes)
- EarthSpace03 pack: Earth from geostationary orbit (3 skyboxes)
- EarthSpace04 pack: Earth from low Earth orbit (3 skyboxes)
Nebulas
- Nebula Skybox Pack #1: 6 skyboxes
- Nebula Skybox Pack #2: 6 skyboxes
Skybox Packs
- SpaceEngine Skybox Pack #1: 9 skyboxes
- SpaceEngine Skybox Pack #2: 5 skyboxes
- SpaceEngine Skybox Pack #3: 9 skyboxes
- SpaceEngine Skybox Pack #4: 9 skyboxes
Other SpaceEngine skyboxes
- Black Hole skyboxes: 2 skyboxes
- Installation05_01: Features Halo's Installation 05 (1 skybox)
- MoonWaterHorizon skyboxes: 2 skyboxes
- StarField skyboxes: 2 skyboxes
These skyboxes feature either 1024x1024 or 2048x2048 faces. Most of these files are compressed with either BGRA8888 or DXT5. I've found DXT5 to be about as good in quality as BGRA8888, but with a much smaller file size. The only major difference I found between DXT5 and BGRA8888 are with sun halos, in that sun halos are a lot more apparent with DXT5 than with BGRA8888. Fortunately, skybox faces don't need have the same compression format, so some faces can be DXT and other faces can be BGRA8888.
And now some screenshot samples:
MoonHab_02 (from SpaceEngine Skybox Pack #1)
Spoiler [Blocked Image: https://i.imgur.com/NUlknJk.jpg]
EarthSpace03 (from the EarthSpace03 pack)
Spoiler [Blocked Image: https://i.imgur.com/YTfzdtu.jpg]
Nebula_04 (from Nebula Pack #1)
Spoiler [Blocked Image: https://i.imgur.com/qLBYFsD.jpg]
Installation05_01, on the map csgo_halo_ascension (my CS:GO port of Halo's Ascension map)
Spoiler [Blocked Image: https://i.imgur.com/FqRMIUb.jpg]
IceMoon_01 (from SpaceEngine Skybox Pack #3)
Spoiler [Blocked Image: https://i.imgur.com/lAbJLoV.jpg]
VenusLike_02 (from SpaceEngine Skybox Pack #4)
Spoiler [Blocked Image: https://i.imgur.com/i8O6fw1.jpg]