phooooo...
I agree, mostly, with -david-. I've got a few things to say:
1. Blend the background. Your background has way more of a jpeg-compression look than the foreground.
2. Apply lens flares last. This'll fix the odd appearance david noticed. Lens flares are an in-camera effect, so they appear on top of everything. That's why I don't use them too often...
3. Yes, your asteriods look a bit smooth. Get a nice, rough texture for the bump and apply it! That, or work some magic with the mesh.
4. To me, your planets look a bit unrealistic. The one with the "arc" on it is kinda funky, and the plain one, though it may be a plain gas giant, lacks any kind of texture or detailed appearance.
5. Don't just use some cloud filters for nebulas. "Clouds" is old and kinda ugly if not used right (you were pretty good in your use though). If you use clouds, customize a bit! Darken areas with the airbrush in PShop, and use the smudge tool.
6. Beams and weapons: try to find something that makes glowy stuff in your program. For me, I can use point and tube lights with glows for projectiles and beams. Objects make lousy beams. And, Meowx is right about the beam golden rule: try not to show the end. If you really can't render them, try adding them post-process with Photoshop.
7. Small lights: it's just a texture. First you have to learn about making textures, then it isn't too difficult (though more difficult that just textures) to make a little-light texture.
8. Lighting: there's no light source coming from your lens flare! At least make a little light coming from anything bright enough to cause a sun-style flare. Also, high-angle lighting is more dramatic...eg. coming from the side or top. For space scenes, turn ambience off or make it the color of the surroundings (here, dim red). Also a good effect is a back- or fill-light, which shines subtley on the shadow areas, or very high-angle (only a thin crescent of light peeking around an object is seen) can make for a good image, and coloring that light can make for a cool effect.
9. Camera: not bad, but for action scenes get up close and personal! Right now it's kind of like "space scene, and oh yeah there's a few ships shooting at each other in the middle". Make sure the largest part of the image is the subject, in general (there are exceptions). Also, on the ships themselves, try for some more dynamic angles. It's almost planar now, with the way they're facing and where they are. Not too exciting. Also, all the ships are bunched up. Have a few stragglers racing in to get a part of the action, someone circling back around, several driving foreward aggressively. There's little difference in the distance between your ships in this scene - they're kind of evenly spaced. Another note: 5 ships does not really make for a particularly intense battle scene.
I'd post some examples, but they're my submissions for the graphics competition: they're not really supposed to be seen until the voting begins, and they're anonymous for the voting.
I hope my comments helped. Look for me after the graphics competition voting ends.
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