I have been exploring the idea of generating a movie quality rendered image of earth. I think most people who have done digital modelling have made an 'earth' in their early days..Lets face it, it is pretty easy to wrap an earth texture to a sphere and render it...and we were all making spaceships back then. :)
However if you want something that will look good at high resolutions and animated then it gets a little more complicated. The basic idea is still the same but we have to up the ante in terms of the assets we use.
There are 3-4 basic model elements in the scene...all geo-spheres with 24 segments. There is an earth or Terra sphere, a cloud sphere, an atmosphere and optionally a much larger background sphere for a star-map. The stars would probably better done in After Effects or something similar but its fine for this. Make sure all spheres sit at 0,0,0 for now. There is also a single directional light to simulate light from the sun
Thanks to people like NASA and their Blue Marble project we now have access to very high resolution imagery of our home-world. Some of the imagery you can use can be found with a simple google image search but some of it will have to come from resources such as this. Basically use the highest resolution you think your computer can manage. The colour image of earth used in the animation below is about 21,600 pixels wide, the largest I could find!
We will combine a few different images to make the earth globe.
The day and night maps will be combined in a composite material. A falloff effect based on the lighting direction will create a dynamic mask that shows the day-lit version in the lit half of the model and the nighttime texture in the unlit side. We'll also end up with a nice graduation between the two which we can adjust as necessary.
The cloud layer is a grey-scale image with an opacity effect..This must be as high res as the other textures otherwise you won't be able to get too close with out seeing blockiness.
The atmosphere texture is a simple fall-off opacity map though it needs to be very subtle.. If you get it right it really sells the image.
Ok, that's the overview/introduction....Part 2 will follow shorty with details and screen grabs.
However if you want something that will look good at high resolutions and animated then it gets a little more complicated. The basic idea is still the same but we have to up the ante in terms of the assets we use.
There are 3-4 basic model elements in the scene...all geo-spheres with 24 segments. There is an earth or Terra sphere, a cloud sphere, an atmosphere and optionally a much larger background sphere for a star-map. The stars would probably better done in After Effects or something similar but its fine for this. Make sure all spheres sit at 0,0,0 for now. There is also a single directional light to simulate light from the sun
Thanks to people like NASA and their Blue Marble project we now have access to very high resolution imagery of our home-world. Some of the imagery you can use can be found with a simple google image search but some of it will have to come from resources such as this. Basically use the highest resolution you think your computer can manage. The colour image of earth used in the animation below is about 21,600 pixels wide, the largest I could find!
We will combine a few different images to make the earth globe.
- A true-color image of earth in daylight
- A night-time image of earth.
- A grey-scale bump/displacement layer
- A specularity layer (so the water shines but the land masses do not)
The day and night maps will be combined in a composite material. A falloff effect based on the lighting direction will create a dynamic mask that shows the day-lit version in the lit half of the model and the nighttime texture in the unlit side. We'll also end up with a nice graduation between the two which we can adjust as necessary.
The cloud layer is a grey-scale image with an opacity effect..This must be as high res as the other textures otherwise you won't be able to get too close with out seeing blockiness.
The atmosphere texture is a simple fall-off opacity map though it needs to be very subtle.. If you get it right it really sells the image.
Ok, that's the overview/introduction....Part 2 will follow shorty with details and screen grabs.