So I'm pretty sure this is a standard issue people run across because I remember reading about it a few years ago (Long time lurker, first time poster here lol), but I have no idea how to go about fixing it... Any help would be appreciated.
This happens on full renders too, but I can't be bothered waiting for a full render when I know that it's going to look the same.
Isn't this an issue with the GI pre-pass or something?
I'm rendering with Terragen 3.3
(https://41.media.tumblr.com/65a30b440e2050d685edf021fefb2cba/tumblr_o2fz64CrzA1tsodnno1_1280.png)
Are you using a cloud for your fire?
If so, try to put the acceleration cache to "none" in the Optimisation tab. I had this a couple of times.
Agreed, this is probably due to use of Acceleration Cache in one of your cloud layers. Often this can happen with very low density, soft clouds used for e.g. haze.
- Oshyan
You can also use the "GI cache file" which allows you to first calculate light / shadow values for the whole image and save it. Later you can use it to ensure that all render buckets use the same light settings. I had the same problem some time ago and it solved the issue.
GI Caches are very useful but won't help if the problem comes from the Acceleration Cache in clouds.
- Oshyan