Underwater distance fade/fog simulation

[branskyj]

Hi all,

I am doing an underwater scene and was wondering how to achieve the going-into-nothing look typical for most underwater scenes without any post production.

I found a nice tutorial (the tutor was using Mental Ray unfortunately) where VRayEnvironmentFog was used as an atmosphere Effect. I used it in VRay with much less success. I also used a plane object just under the sea surface (positioned far away from and facing the camera) which has a gradient ramp map applied to simulate how the color changes from bottom to top but I still get hard line where the plane meets the sea surface. The natural blur in the depth is missing.

 

Is that what normally is used to achieve the desired result?

I am attaching an image of what I am trying to achieve.

 

Thank you very much.

[braddewald]

Why don't you want to do it in post? It seems like with photoshop a few adjustment layers and a z-depth pass would give you all the tools you need.

[branskyj]

It is an animation, not a single render. I am somewhat experienced in Photoshop and can handle a single render, but have very poor experience with Premiere/After Effects/Vegas etc.

Thanks.

[braddewald]

As somebody who just completed their first (very short) fly through animation and tried to teach myself After Effects in the process, I feel your pain.

 

Even so, rendering a z-depth pass and using a lens blur adjustment layer in After Effects tied to that pass is fairly straightforward and there are a lot of tutorials about it out there.

[branskyj]

Congratulations on your success with video editing.

I suppose that is an option... I will look into it and see if I'll grasp the gist.

 

In the meantime- anyone else with ideas?

 

Thanks a lot Bradley,

Have a good week.

[Nicolai Bongard]

The vray environment fog is supposed to work in a volume, so if your water is an object with thickness you can select that as your object for the fog to "be in". The only thing you pretty much have to adjust is the density (over distance, i use meters, but whatever floats your boat/settings you got in max). But if you somehow cannot make it work, you should consider the zdepth pass method mentioned earlyer. Its been a long time since i did any animation, but you should be able to save your frames in sequence as still images, and do the same with your z depth pass. Then you can "assemble" them as a video in your video editing software. Then you basically do as you would do in photoshop, load up your film, then create a layer above with blue color or blur or whatever you need, and use your z depth film as a mask. Sorry i cannot be of any more help, but good luck!

[branskyj]

Thanks a lot, Nicolai.

I guess I am going back to the Mental Ray tutorial and will try to replicate it in VRay.

Hope it works.

 

Cheers, mate.

[Nic H]

id just use the vray environment fog with a box environment gizmo and adjust the fog distance - its quite simple to set up

with a sun sky, water plane and a ground plane - however for what you want to acheive in that ref image you only need a zdepth pass...

 

if you want volumetric rays you can add another light with a noise in the projector slot to cast the rays.

vray fog is also SLOW!

 

i messed around for ages trying to get murky green water in this (with mixed results) all done with vray env fog

[branskyj]

Priceless tips, Nic. And a really nice video.

 

I will move again to the underwater scene in a day or two (I am currently dealing with the above the water set-up) and will definitely try your idea.

 

Thanks a lot and have a nice weekend.