lightning from sun (with proper spot on the planet)
a planet
Is just a sphere positioned at (0,0,0) for convenience
the stars
Variants to make:
using world shaded with image as environment texture for background shader
using giant sphere with incoming vector / environment texture / emission shader – seems stupid
visible sun
making the disk as an object:
it will notably drift among stars, because stars are angular mapped (as if at infinite distance), and the object is not
making very huge object at very large distance
seems very crazy, the sun actual size is 100 times of earth and the actual distance is unimaginable and probably unscalable into blender units
drawing the circle on an image and combine with stars background texture
seems quite ok to use 16000x8000 image for something like 16x16 circle
lightning
using “sun source”
will make parallel light rays and the light spot on the planet will disapear while sun disk still visible (and should be reflected on surface)
using “spot source” or “point source” with light falloff = constant
will move light in desync with sun disk on sky, because it is closer then infinity
using some object with emission shader - the same as previous
Upd:
Seems like the problem is in fact to synchronize direction of sun lamp with actual position of the sun on the sky.
The position of sun (and stars) on the sky is constantly defined as lattitude/longitude (or azimuth/altitude, or right ascention/declination)
The sun should be oriented so that light flows from visible sun into planet.
Are you wondering how to make the “sun” or how to make the effect of the sun set? If the sunset effect, use the compositor. And Andrew prices tutorial will help you there even though the rest of the tutorial is about BI and not cycles.
I updated post with the picture that shows the problem:
While sun still fully visible (not hidden behind planet), parallel light does not enlight visible part of planet.
Any object, like circle with emission will be move on front of sky stars significally, because it cannot be placed at infinite.
The question is about how to move lamps.
The part of planet “i need” is part that would be lighted by real sun, moving down behind horizon.
I cannot set up lamps manually for every frame.
I think the solutions everyone are trying to give you will produce the effect you want. While these solutions are not “physically correct”, they use "smoke and mirrors to poduce the effect you are looking for. With a combination of multiple layers, multiple lights effecting specific layers, and the compositor you can produce the exact effect you are looking for, even though it is not “physically correct”.
I’m not aiming physically correct solution.
But i want astronomically correct solution, this requires sun to be drawn on sky, and not hanging around planet.
If to use lens flare - how could i limit it to be shown only on planet surface and to look like mirror?
i think you are over complicating your scene, you want to animate a sunset from space, the only thing you really need to animate is the camera. the sun is just a spot lamp emitting against a sphere. why would it move? the actual sun doesnt move.
you just need a small disc set to emit which is between the lamp and the sphere to represent the sun so that when you move your camera around the orb the perspective shift gives the appearance of the sun setting. your star map will be behind the lamp so wont be in the way of your, whatever you think it will be in the way of.
if this is what your trying to create, definitely don’t do it in cycles, not yet anyway.
use andrew prices tutorial to create the earth and then add an extra sphere on top around the same size as the 1st layer. Then delete all of the faces on the sphere you don’t want (all except for on the side of the earth), and add another sphere to where the sun is going to be like this:
feel free to sculpt it into the atmosphere/cloud layers if it doesn’t look too flash.
then add in a halo for the streak effect and then move onto the compositing:
If you’re trying to fake the paralax of a much distanter (is that a word?) Sun without actually placing it that far away, perhaps you could use constraints and/or drivers to make the Sun move as a function of the position of the camera?
