Spent about 4 hours (last night) tweaking a mesh that will be rendered 'behind' the level in order to give the impression of distant features. In this case, I have steep walls either side of the level to give the impression of being at the bottom of a huge, dark trench.
Then it was a matter of adding a number of layered, blended flat quads above the player with a blobby, additive cloud texture, to give the impression of drifting, volumetric clouds above the player.
Then spent time tweaking fog range and colour to match. Then spent time tweaking surface colours to match the lighting conditions (reddy-orange, murky). It's getting there but it's not there yet.
Then it was a matter of adding a number of layered, blended flat quads above the player with a blobby, additive cloud texture, to give the impression of drifting, volumetric clouds above the player.
Then spent time tweaking fog range and colour to match. Then spent time tweaking surface colours to match the lighting conditions (reddy-orange, murky). It's getting there but it's not there yet.