Underwater Scenes

[sjefen]

On Terragen 2's Frequently Asked Questions page you will find this one:

Will it be possible to render underwater scenes?
Yes, it will be.

I was just woundering how this will work. Will it be like whenever I take my camera under the sea, or lake, it will become a underwater scene like in the picture below? (I'm taking about the greenish depth). Or do we have to tricks an mix to pull it off?

http://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Plitvice_underwater.jpg/800px-Plitvice_underwater.jpg

[dhavalmistry]

I am guessing it will only be possible to do once the transparency is implemented.....making underwater scenes are gonnna be tricky.....it will be challenge to get underwater algae and rock formations....

[sjefen]

Yes..... but it will be fun

[cyphyr]

I'm sure that this is connected to the implementation of the transparency however I doubt it will have the automatic depth effect you seek. A more useful way forward would be to use the atmosphere controls to simulate depth haze in a similar way. That way you could simulate different kinds of water, tropical, murky, tidal etc. Cant wait
Richard

[sjefen]

Then I don't think it's fair to say it can do underwater scenes. It's more like: you are able to render even if your camera is under the water. It will become more like a workaround, and I look at a workaround's as a more fake way to get the desired result.
Maybe I'm wrong. It's just my impression.

[cyphyr]

Surely with any digital art its all really just a work around ... If we get the results we're looking for then what dose it matter how we actually get there (so long as its not too tedious). I'd love to be proved wrong but I know true under water environments are particularly difficult to achieve with the same level of accuracy and subtlety that we're used to in TG2. It would not too be hard now to make a passable under water scene now but as you say iot would require a lot of workarounds. I might have a go later

Richard

hehe Just had a quick attempt and got no where ...  fast lol
Loads of Haze, I mean loads (5000+) and as many things as I could think of to cast some sort of caustic shadows/highlights

[sjefen]

You are right. When I think about it, it dosen't really matter how we get there.
But I still hope there will be options for underwater scenes

[DanD]

Umm,Up the haze amount 7 or 8 to start with add a high plane, texture that with any water surface texture, adjust haze height till it meets the plane,add color, and Viola !!! underwater scene

[sjefen]

I understand this is one way to get there, but I don't think it's right. Atmosphere is not the same as water if you know what I mean. For example.... I don't think the light in the atmosphere and the light in the water is getting calculated the same way. I hope you understand me

EDIT: Doesn't Vue do underwater scenes?

[Will]

kinda, its just a transparent terrain or an infinite plane with a material, you have to raise the haze levels to get a convincing shot.

[Cyber-Angel]

If your going to do underwater scenes and rendering then you are going to have to look at treating water as a participating medium http://www.schorsch.com/kbase/glossary/part_med.html due to the particulate mater found in water, sediment, phytoplankton etc and the way light scatters through water when your under it.

My understanding is is that light underwater is involved with multiple scattering not just single scattering in the forward direction that some papers on rendering underwater scenes would include in their models and should not be included in Terragen if at all possible.

Type "Participating medium for underwater rendering" into Google brings up some interesting papers on the subject for any one wishing to learn more about the current state of thinking and I may suggest that the Methodology employed by Terragen be a combination of several differant methods to produce the most realistic results.

Regards to you.

Cyber-Angel       

[sjefen]

So.... what does the Planetside team have to say about this?

[Matt]

The first 2.0 release will render transparent surfaces, so if the camera is above the water you will be able to see underwater and if it is underwater you will be able to look up and see out of the water in some places.

The attenuation of light underwater (due to participating media) can be simulated pretty well using appropriate atmosphere settings, but this is not an ideal solution for two reasons: there is no way to prevent the underwater atmosphere from reaching above the surface of the water, and the default settings are not designed for underwater scenes. Nevertheless, it is already possible to render convincing underwater scenes.

Beyond version 2.0, I think we may develop a new volumetric object type for Terragen (similar to the cloud layer or planet atmosphere) which is specifically designed to render underwater volumetrics, i.e. it will be possible to contain the volumetric medium below a particular height so that it does not reach above the water, and it will come with presets for a few different types of underwater conditions. Behind the scenes it will work very similar to the planet atmosphere or cloud layer, but it will make it easier to render realistic underwater scenes that fit in with the rest of the scene.

Looking further into the future, I hope to get the the underwater volumetrics to respect the water levels defined by other water objects such as the Lake object, but that will take longer to develop.

Matt

[sjefen]

Thank you very much for the answer Matt. Looking forward to this.

[Cyber-Angel]

Matt,

Will the initial system permit the creation of what are known as "God-Rays" those shafts of light seen just below the surface under certain conditions, or would this only be possible with the volumetric system planed for the future?

Regards to you.

Cyber-Angel