01-07-2008, 07:10 AM
Well, the issue is that noise changes tones per pixel, so in general a pixel is the size of any given star when using that technique--in later steps they get a little bigger, but not much. At larger resolutions, those "star pixels" were invisible at normal viewing distances, so the only thing you could do is scale them up by about 2000% in my case. At that scale the artifacts are unacceptable.
Just stitching smaller fields doesn't actually make anything better -- it makes a great extremely large star field at very low resolution, but not such a great normal sized, high resolution star field.
However, I figured out a way! I'll post the actual settings for the brush later today maybe, but I came up with a brush in photoshop that looks dead on like the base star field-- I'm really happy with how it looks, and it's WAY easier to use than greg martin's technique. It's far more flexible because it's a brush, so you can paint in any color, over any background, with any number of layers.
You can create a similar brush easily -- for my 9000x7200 resolution, my basic shape was 50px. I set the roundness to 80%, hardness to something high but not quite 100%. I then set the dynamics such that each star is a different opacity, size, and rotation. I gave it a wide scatter area to get randomness. I'll post all the settings later, like I said, but it's easy to set up if you play around with it. It's also super easy to scale it up and down for whatever resolution you're using.