[watsisname]

Oh, Earth was just having really spectacular weather at that moment. 
Nah, I left it cloudless to demonstrate how it looks when placed over the planet texture.  I thought clouds would get in the way a bit.

Why is the haze circular-looking? Shouldn't it be an ellipsoid extending from pole to pole like the terminator is?

My understanding is that the intensity of the haze is dependent on the amount of air that a ray passes through going from ground to the observer (same reason why distant mountains look bluish), so it's strongest at the limb and decreases toward the center of the disk, which would imply a circular effect if the planet is in full phase.  (See image in orbiter below).  But obviously if the planet is not full phase, then the haze intensity would also depend on how strongly lit each portion of the surface is, being strongest at the sub-solar point and weaker near the terminator.
The intensity of the haze, and how rapidly it drops off going away from the limb, are up to artist choice I think.  So far I haven't been able to find a good photo of earth that shows this well, but my preference is for it to be a bit strong but also spread out.
Lastly colors should become redder closer to the terminator, and even more so when viewed from the darkside (crescent phase planets), to account for Rayleigh scattering.

Full-phase earth in orbiter:

[qazwsx]

It just seems like everyone goes over the top with this atmospheric bloom/glow stuff...

attached is an oldish jupiter render, glow feels a bit to strong, but the bluer rim shading is done with composite nodes in blender

[attachment deleted by admin]

[Herra Tohtori]

You might want to use Minnaert shader instead of Lambert.

Also, Jupiter should have no atmospheric glow around it as seen from distance like that. Just clear transition from space to planet.

[Retsof]

Is that texture from a NASA image?  I experimented a bit in GIMP with making gas giants but can't find a good way to make the storms unless I were to do it manually.

[eldain]

well, star out big with large coloured stokes, then use the Iwarp (liquefy equivalent of photoshop) to make your swirls and storms,
takes some training but I manage to do it fairly reasonable.

Also, Jupiter should have no atmospheric glow around it as seen from distance like that. Just clear transition from space to planet.

not sure about that, I mean if considering its gas giant nature, the whole thing is one atmosphere, so a little fall off wouldn't hurt, if rendering it for one hides hard edges. The glow is just not as dominant as on earth like planets which I think is because of the scale.
(radii are approx. 1: 22 )
Ill post some of the planets i'm working on in photoshop, once we release them on the diaspora-dev tread.

eldain

[watsisname]

With Jupiter, there is a haze layer at 0km altitude (0.1 atm pressure), with cloud layers appearing about 30km below this point.  Pressure drops off to 10^-3 millibars at 320km altitude so let's consider this to be the boundary of the visible atmosphere, thus the visible depth of the atmosphere is approximately 350 kilometers (obviously this is a very wish-washy figure since it's hard to say how high up the upper boundary of the visible atmosphere is, but probably 300 to 400km is a reasonable estimate).

Jupiter's equitorial radius is 71492km, so using the 350km estimate of visible thickness, then the ratio of atmosphere to planet radius is 350:71492, or 1:204.  You could consider this to mean that a Jupiter planet bitmap of 2048 pixels radius should have an atmospheric halo effect of only 10 pixels thickness.

Doing the same calculation with Earth, we can estimate the ratio to be about 100:6371, or 1:64, which is about three times more prominent than Jupiter's.

[eldain]

edit, ___> thats what I meant



eldain

[Herra Tohtori]

With Jupiter, there is a haze layer at 0km altitude (0.1 atm pressure), with cloud layers appearing about 30km below this point.  Pressure drops off to 10^-3 millibars at 320km altitude so let's consider this to be the boundary of the visible atmosphere, thus the visible depth of the atmosphere is approximately 350 kilometers (obviously this is a very wish-washy figure since it's hard to say how high up the upper boundary of the visible atmosphere is, but probably 300 to 400km is a reasonable estimate).

Jupiter's equitorial radius is 71492km, so using the 350km estimate of visible thickness, then the ratio of atmosphere to planet radius is 350:71492, or 1:204.  You could consider this to mean that a Jupiter planet bitmap of 2048 pixels radius should have an atmospheric halo effect of only 10 pixels thickness.

Doing the same calculation with Earth, we can estimate the ratio to be about 100:6371, or 1:64, which is about three times more prominent than Jupiter's.

Good work.

This is what I mean - the relative height of the visible atmospheric haze is so small that, in most images and renders, it should be covered by anti-aliasing of the edge of the sphere. In fact, same holds true for Earth as well for most shots taken from high orbit or further; the atmospheric haze really is only visible from LEO.

And that's a 2048 pixel radius. That means the bitmap itself should be at least a whopping 4096^2 in size. Not really useful for a background bitmap...

Now, with the available textures for Jupiter, making a render of this size makes little sense because the source textures' resolution starts to be at or beyond their limits - ie. the surface starts to pixelate.

The problem is even more pronounced if you're making a skybox (which, IMHO, should be the preferential method of putting planets on the background). If you wanted any sort of haze to be visible, you would have to put the camera so close to the planet that the textures would be atrociously pixelated. You would have to blur the basic diffuse texture, then somehow add your own high-resolution imaginary cloud system details - doable, but rather tricky for obvious reasons.

[eldain]

Just because of that I start with a 8192^2 picture, which I transform and then downscale to 4096^2, just because you lose information
when transforming (in photoshop that is, its less apparent in renders as it crops outward, leaving the closest part as the standard "normal" resolution)

secondly, that it might not be visible clearly on the outside is one thing but fall "off", falls inwards as well. I always feel, (and that is my personal opinion) that the inward glow and outward edge blend better if you use a fall off, even when only very small and on the brink of being visible at all.

eldain

[watsisname]

I agree, eldain.  I think in most cases a bit of a fuzzy atmosphere halo looks better than a pure crisp edge, especially if you're dealing with aliasing.  I like seeing how things should look in reality but sometimes some stretching of the truth is not a bad thing either.

[ShadowWolf_IH]

my first planet, no atmosphere yet.

[Droid803]

Thats a very big white area.

[ShadowWolf_IH]

Wrong link 

[FreeSpaceFreak]

I can see a black square around the planet, and the nebula is over everything else too. But the surface is pretty good, it really looks like a rocky moon, battered by meteors

[ShadowWolf_IH]

I figured the square out and know what I did wrong, it won't happen on my next attempt.  Thanks for the vote.

[watsisname]

Nice first planet!  The surface texture looks good, and the nebula/starfield is a nice touch.  One suggestion I'd make is to move the shadow layer a little -- it's not quite covering enough of the planet so it looks more like an eclipse shadow.  'Tis a minor nitpick though -- great work overall.


On an unrelated subject, I was curious about figuring out the details of how different parts of earth look like [color-wise] from a great distance.  I'm thinking maybe the color information might be useful when making surface textures and atmospheric effects in future renders.  For my reference image, I used a photo taken from Apollo 16 of the earth in gibbous-phase, and did a little bit of adjustment in GIMP to get the colors closer to what I think they would look like to the human eye.  Here's how it looks after adjustment:

*original image here:  http://img293.imageshack.us/img293/5792/as1611818885.jpg

I checked this out further in GIMP with the color-picker tool and made a list of the actual colors over various parts of the image, specifically for what the desert/forest/ocean regions are in the center of the planet disk, and how the ocean color changes as you get closer to the limb, and lastly, the sunset colors.  For some things I averaged the colors over several regions to get a better determination... the true accuracy of this obviously depends on the camera and its settings used to take the photo, plus it's all skewed by my altering of it, but the result is still pretty photo-realistic in my opinion.  One thing I found rather interesting is how similar the forest color is to the ocean color... it's not so much "greener" as it is "lighter", as you can see below...

Regions selected:


Resulting color:

[Aardwolf]

Awesome. 

[ShadowWolf_IH]

and 2.

[ShadowGorrath]

Something's wrong with the edge of the shadow.

[headdie]

Something's wrong with the edge of the shadow.

the shadow works nicely going from dark to light but there is as sudden change from about 25-50% gradient to clear with an odd artifact along the transition emphasising the fact.

also I'm not to keen on the hazy blobs which i presume to be clouds, the lack of definition contrasts horribly with the nicely detailed layer below it, and i think the blobs can be happily dropped as the layer below is awesome some and has a slightly menacing alien feel