planet armospheres

[Guest]

I switched to V-Ray from FinalRender earlier this year. I used to make planet atmospheres either with Sitni Sati's ScatterVLPro and Void (which has been discontinued) or a normal-inverted sphere around the planet with an additive material applied (which I can't do in V-Ray).

Has anybody any good ideas for making atmospheres without the need for a composite?
Thanks.

[anthonyh]

Use https://www.videocopilot.net/orb/ if you have After Effects. It`s way faster. It`s also free.

[Guest]

Thanks.
Unfortunately I have to work in 3ds max - all my renders are dome-based.

[super gnu]

well you could use an inverted sphere with a falloff in the opacity? then do whatever you want with the actual material? or you could use a non-renderable sphere and use vrayenvironmentfog to do a proper atmosphere, or a vdb file? or vrayscattervolume material maybe?

[Guest]

Thanks. I'll try the volumetric methods.
An inverted sphere works great with an additive material, but I was told there is no way to get an additive material using V-Ray.

[Paul Oblomov]

I wish that one day there would be rayleigh scattering in vray or phx. Or volumetric OSL support.

[rusteberg]

Here's another option worth looking into:

[Guest]

Thanks. That's the inverted sphere which I used to use sometimes. Unfortunately it's not as good in V-Ray in the absence of additive settings.

[dgruwier]

Don't make it additive or self-illuminated if you're going for any kind of realism. You want the atmosphere and earth to cast/recieve shadows from each other.
I made the atmosphere for these two renders a long time ago using just a diffuse sphere with opacity and color controlled with falloff (Like rusteberg showed, but with a dip at the end of the mix curve to make it fade out cleanly towards the edge of the atmosphere sphere)

I wish that one day there would be rayleigh scattering in vray or phx. Or volumetric OSL support.

Precise rayleigh/mie is not necesarrily required if you just use the vrayScatterVolume. Unfortunately I don't have access to vray atm so I can can't create a new example file, so quickly I recreated it in Blender, but the principle and the result is nearly identical (use vrayDistanceText to control density from the planet, set the color to somethinb blue-ish). Notice the red "sunset" and the clean white/blue horizon. It can be made better than this with some more time to work on it. This is the method I would use if I made an earth render today, only downside is that it's super slow to render.

[Guest]

Don't make it additive or self-illuminated if you're going for any kind of realism. You want the atmosphere and earth to cast/recieve shadows from each other.
I made the atmosphere for these two renders a long time ago using just a diffuse sphere with opacity and color controlled with falloff

Thanks for the examples.
Coming from FinalRender, I knew I'd have to re-learn a lot of stuff in V-Ray, but I didn't expect there to be such a huge different in render quality. It would have been next to impossible for me to get a render looking as good as that first image using inverted sphere + falloff. Additive was necessary to give the image a little boost.

[japetus]

Sorry this is old, but I've been trying to do a convincing planet atmosphere too (you'd think it'd be easy), I"d like to know more about that scatter volume approach, I've used another scatter volume setup different from this, but with not great results, it tended to really darken the planet underneath. Could you explain more about that?

[super gnu]

Precise rayleigh/mie is not necesarrily required if you just use the vrayScatterVolume. Unfortunately I don't have access to vray atm so I can can't create a new example file, so quickly I recreated it in Blender, but the principle and the result is nearly identical (use vrayDistanceText to control density from the planet, set the color to somethinb blue-ish). Notice the red "sunset" and the clean white/blue horizon. It can be made better than this with some more time to work on it. This is the method I would use if I made an earth render today, only downside is that it's super slow to render.

i have bashed my head against this technique for days.. getting the volume to fade off nicely to completely transparent at the edge/outside seems impossible.. ive tried distance tex driven from earth surface, falloff maps etc etc, but it just always has a noticeable hard edge, even with the max radius cranked wayyy above the maximum possible in the interface, using maxscript. apart from that, it looked good and rendered quite fast actually. maybe it works better in blender in this regard.

[japetus]

i have bashed my head against this technique for days.. getting the volume to fade off nicely to completely transparent at the edge/outside seems impossible.. ive tried distance tex driven from earth surface, falloff maps etc etc, but it just always has a noticeable hard edge, even with the max radius cranked wayyy above the maximum possible in the interface, using maxscript. apart from that, it looked good and rendered quite fast actually. maybe it works better in blender in this regard.

Yeah that's what I'm bashing my head against too is the nice falloff into space...super frustrating! I'd rather not "just add a glow" in post

[dgruwier]

When I did this in vray, I used the distance tex, then something like the output node to add a steep curve to it, so it's exponentially more dense near the surface.