[C4DtoA] Realistic planet atmosphere?

[Andre_Thegiant]

Hi,

first of all, I'm well aware that this question has been asked before, but so far I haven't encountered any solutions that actually worked. I'm sorry if this is seen as spam, but I'm really struggling with this.

I'm currently working on a project where I'm trying to recreate a low-orbit view of the Earth from space. Currently I'm stuck on trying to make the atmosphere look correct. I've scoured the forums in search of answers but the techniques were either outdated or just didn't work for some reason, most likely due to differences in programs (Houdini, Maya, C4D, etc.).

I've tried using the standard shader transmittance depth technique (found here: https://drive.google.com/file/d/1vpvFwhwDqX1Je0zhzAKDM9bY_NOKbPny/view),

and using an Arnold Volume with a standard volume applied to it (found here: https://docs.arnoldrenderer.com/display/A5AFMUG/Shading+a+Globe)

but none of this worked. Both techniques resulted in harsh edges that couldn't be feathered and didn't allow for any proper colour control of the atmosphere falloff (I'm working in ACES, so colour profile shouldn't be the issue).

In both cases I even tried following the tutorials value by value, even dowloaded a C4D scene from Lee Griggs (found here: https://answers.arnoldrenderer.com/questions/28072/how-to-render-planet-atmosphere-with-arnoldrender...) in hopes of studying it, but that scene itself had harsh edges and offered unrealistic results upclose.

If anyone knows of any technique in Arnold (C4D) that would allow me to actually render a proper planetary atmosphere from up-close I would be sincerely grateful.

[nwoolridge]

Try adding a facing ratio shader to the transmission weight channel for the atmosphere: bias 0.84 and gain 0.15 worked for me...

[Andre_Thegiant]

@Nicholas Woolridge, thank you for your answer, I managed to get marginally better results thanks to your suggestion. Although I'm still faced with the harsh edge of the mesh that the standard surface shader is applied to - is it possible to somehow 'feather' that edge, perhaps with the cutout opacity parameter? Or any other technique for that matter, I'm still somewhat new when it comes to Arnold, hence the questions.

Below I attached an image of what I mean by 'harsh edge' - notice the lack of falloff which is present in a real atmosphere. Apologies for the bad render quality, this is only meant as a preview of sorts.

Again, thank you for your help Nicholas, I sincerely appreciate it.