CompuServe Thread

#Atmosphere

4 messages in this thread
#96333From: Jeff ALuApr 9, 1994 7:40 PM
Hello, I am trying to construct a planet surrounded by an atmosphere. I've constructed two spheres, one larger than the other, where the larger sphere is the atmosphere sourrounding the planet. The atmosphere is a pale blue hue, on a black star background. The atmosphere needs to get thinner as it moves away from the surface of the planet. I need the blue to blend right in with the black background as it thins out. I've used the transparency settings to do the astmosphere, and trasparency falloff to increase the transparency of the larger sphere around the edges. The problem is that I can't seem to get the edges of the sphere transparent enough to blend into the black background, so the atmosphere dosen't look very convincing. Any Ideas how I can achieve this blend? Thanks! Jeff
#96345From: MARTIN G FOSTERApr 9, 1994 9:02 PM
Jeff, you could use an opacity map. Create it with animator pro, or a similar paint package, using a grayscale pallette and rgrad (radial gradient) ink. It would be need to be a solid white circle on a black background with a gradient of white to black around the outer edge. You could map this planar to the atmosphere sphere object. It may only work if you stay at the same camera angle to the atmosphere. If you go around the planet you might have a problem and I can't think of a solution for that other than post-processing a haze in video post, or similar technique.
#96377From: Jeff ALuApr 10, 1994 11:23 AM
Unfortunately, I do need to travel around the planet about a quarter of a rotation. I suppose maybe I could rotate the outer sphere (atmosphere) in conjuction with the camera. Thanks for the help! Jeff
#96532From: MARTIN G FOSTERApr 11, 1994 11:25 AM
Jeff, glad to help. Maybe rotating the outer sphere to face the camera would work. You'd need to render it to see.