I just finished this video: it is mostly done in Unreal 5.3, but all the skies are made in Terragen 4.
https://youtu.be/NSt9E0wnIYoFor the last shot, I used a new workflow: I started in Terragen Sky to get some interesting cloud formations, then imported these in my Terragen project.
That allowed me to quickly iterate through different cloud looks, and retain some very much-needed rendering performance.
The first and last shots were rendered at HD resolution, and then upscaled and denoised with Topaz Video AI.
The last shot needed two iterations to get it clean.
One thing I could not make it work is OCIO: I use the Maya 2022 OCIO config which is ACES v2, and that config works for everything across the board (including Adobe!), but Terragen chokes on it... Very unfortunate as it was laborious to get the renders to look they look now in my video: rendering in ACEScg would have made it a lot easier.
I know I could switch back to ACES 1.2, which I think works with Terragen 4.7, but I was juggling a lot a different software packages that require ACES 2 and I did not want to rock the boat as it took days to render these shots on my machine.