I'm attempting to use the compositor to blur a test render. I'm hoping to make a scene where I fly through a space filled with stars of various sizes, colors and brightnesses.
To visually underscore the brightness of the stars, I'm using the Gaussian Blur node in the Compositor. I was hoping that the brighter stars would have "glare" that changed in size and intensity depending on the brightness of the star and its emission strength.
But, before I do this, I'm running up against an issue that I can't resolve. I'm getting a bizarre looking "square" blur when I crank up the size of the blur beyond a certain point.
Here's my test image before the composite blur is added:
And here is the image after the blur is added:
Here is what happens when I use the "glare" node:
I'd like the blur to be circular.
Exporting the files and adding the blur to individual images in After Effects or Photoshop would not work, because these programs cannot distinguish the between a rendered object that has an emission from a small or large object, or differentiate between an object that has an emission strength of 1 from one that has one of 100 (as Blender can):
Left icosphere: emission strength 2 Middle icosphere: emission strength 20 Right icosphere: emission strength 200