Regarding atmospheres I have something to say.
I don’t know if a glow effect is the best choice for creating the atmosphere ring, considering that the atmosphere doesn’t really glow, but it’s actually a haze effect of slow attenuating, diluting of the atmosphere towards space we’re after.
As can be seen from a picture I’ve rendered a long time ago in 3ds max, it should look something like this. ( the picture lacks the bluishness in color, caused by the bluishness of the atmosphere, but that’s not important here, and it appears there is no land, because it’s the Pacific - you can actually see a part of Hawaii beneath the clouds in the upper right corner).
I actually don’t remember how I’ve done it, I believe it was a glow effect, but it’s obvious it doesn’t glow on the inner side of the planet/space border. The whole glow оn the inside of the border of the planet and space doesn’t look really nice and photorealistic to me. If it could somehow be avoided, by specifying the glow effect to only show on the outer perimeter of the border, it would be great. ( the glow is maybe to strong even on this image, considering how pictures of the Earth actually look like, but that’s another issue, and that way it almost wouldn’t even be visible).
If the glow effect you’re using doesn’t end up being flexible enough, it could be achieved by different means. Simply use a ring shape with the appropriate texture applied to it, actually a single color that becomes transparent going away from the planet; make the ring rotate around the planet with the camera, and in relation to the sun make it change it’s transparency (give a transparency value to the left and to the right side of the ring and change it from none/equal when the sun is behind the camera, to none on the left, full on the right when the sun is on the left, to full/equal when the sun is behind the planet). That would avoid the problem of having to change the strength of the glow effect as you go away from the planet, and tinkering with the glow effect in general (which could be good considering it’s applied to engines and such as well). It’s just a suggestion, I don’t know if it would look good, or even be easy to implement, but I’m just suggesting. You know best.
Just to add, I think the main reason why the ring doesn’t look as good in the viewer is the color. It should be a different sort of blue. This one is too much “ocean” blue, and not enough “sky” blue, in the lack of better terms.
Another thing is the specular highlight I’ve seen in the viewer so far. It seems that the atmosphere is the actual thing that is highlighted, because from what I’ve seen the bright highlight moves even over the less lit clouds. But I have the feeling that most of the highlighting we see on images of the Earth comes from the highlights on the ocean, the planet itself, and not the atmosphere. And as another thing the highlight should show up only on water surfaces because they are more reflective than land. I don’t know if specular highlighting has yet been applied to bump mapped terrain, but anyway, I feel that such a strong highlight shouldn’t, and normally isn’t seen over land, but I could be wrong.
Just to back my claims I’ve added one of many photographs of Earth from space.
