Is there a way to confine the atmosphere to a specific area?

[Anonymous]

I'm creating a type of disc-world and I want it to have an atmosphere, but only in a 'dome' over the surface. The artificial lighting is way above, so I only want it to have a volumetric and diffuse effect as it hits the atmosphere. Any suggestions on how I could achieve this? I'm new to Arnold and relatively new to C4D, so still learning and any help would be appreciated! Thanks in advance.

[madsd · Accepted solution]

Build the dome as a model, a sphere for example and use the Volume material instead.
This way you can make it any shape you want.

[lee_griggs]

Mesh Volume

[Anonymous]

Thanks guys, I'll try those and see how I get on...

[Anonymous]

Ok, I've created a dome, applied a mesh volume tag, and a standard volume shader, and it's working nicely, thanks guys! How would I ramp the density so that it fades towards the outside of the dome and it denser in the centre?

Thanks!

[lee_griggs]

"How would I ramp the density"

You could add a ramp to the density 🙂

[Anonymous]

Lol, thanks! I did try that, but struggling to get the effect I want. I want the edge of the atmosphere to fade out. Currently it has a sharp edge. If I was using After Effects I'd add a glow to blur the edge of the dome, so trying to figure how I simulate or achieve that same effect in 3D...

[lee_griggs]

Inserting a Range shader in-between the Ramp and Density might give you some more control. Can you share images?

[Anonymous]

For some reason I'm unable to upload any renders to share - I keep getting an 'error parsing the uploaded file' message, no matter what filetype or size I use.

I just want to fade the edge of the atmosphere line so it's not so sharp. I tried inserting the range shader, but still not with the desired effect!

[lee_griggs]

What if you projected the ramp? It might give you some more control.

Can you upload the images and/or a simplifed scene somewhere else?

[Anonymous]

https://greyscalegorilla.com/tutorials/volume-displacement-c4d-arnold/ use this tutorial