Underwater scene

Started by René, July 15, 2018, 12:39:42 pm

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Quote from: Oshyan on August 11, 2018, 09:49:46 pm
I *think* you may be able to use two Suns, one with shadows for Surfaces (soft shadows enabled), and the other with shadows for atmo (soft shadows disabled).

- Oshyan

It works, kind of. I get a bit of both, but then I lose quality in other places. Maybe I am looking for something that is not possible in the real world; can soft shadows and caustics exist together at all?
Thanks anyway.


Quote from: WASasquatch on August 11, 2018, 12:56:39 pm
Quote from: René on August 11, 2018, 04:56:29 am
Quote from: WASasquatch on August 10, 2018, 12:49:16 pm
Though there are shadows in caustics. Technically it's what makes the caustics. We just see the light as the "active bits" rather than noting the shadows.

Okay, I'm not an expert in this area  :) although I did some reading on this subject. If it would help to create caustics I would dive into this matter but if it is simply not possible then all knowledge of the world will not help. :-\
How would you explain caustics on the bottom of a boat? Reflections?

I don't want to get into a argument. It's why we call them caustics, instead of just refraction (like a kaleidoscopes refractions), because they involve refraction and shadow of objects. The transparency and refraction effect the basic shadow as well. Ocean floor caustics includes shadows when light is refracted away, shifted and concentrated with other light. This creates shadows... The light itself is refraction. The combination of the two is caustics.

This is also why the shadow on a boat includes different depths as well as focused highlights of refraction from redirecting light. You'd imagine at a distance your focused highlights are actually going to be pretty drowned out and you're mainly getting shadow forms. For example, you mentioned 150m? You won't see any focused highlights, and the filtered colours will be non-existent. Mainly just shadows.  In fact, in most the ocean; darkout.

Without actual refraction from the reflective surface shadows and lighting highlights is the only way to fake it. Wouldn't be realistic with ocean surface lot like the day with refraction highlights

Thank you for your elaborate explanation. There is a lot more to it than I expected.


Quote from: René on August 11, 2018, 07:18:03 am

I like this very much! And as I see you have solved the problem with overlapping population-instances.
Absolutely marvelous!


September 01, 2018, 10:48:20 pm #48 Last Edit: September 02, 2018, 02:11:27 am by WASasquatch
You know I was watching Finding Nemo today and realized their caustics Re just shadows. I than went online and tried to research underwater cameras, and it seems this chromatic effect is just the result of pressurized cameras inside a box viewing through tempered glass. This isn't found in high-end imagining like 8k sports cameras and stuff from National Geographic and Discovery. Leads me to think this is just the quality/condition (surface wscratches wear) on tempered glass often reused even if camera is removed. 

Low contrast darker scenes with bright suddemtransitions creating optical illusions. Even at the pool here at the hotel we're staying at the reflections are just yellow-y sun highlights to the naked eye.

Edit: Finding Dory (Finding Nemo sequel) was on Free Form tonight, and throughout it, the only scene I noticed refracted caustics was the touch tide pool (where kids can touch sea critters) where they showed the water full of lifted silt and sand from kids stirring it up, there they had multiple colours in the refractions, but not in the rest of the movie from what I noticed. Especially in the ocean showing any sort of depth.
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I've never been a huge fan of most underwater TG renders, but these are really good and very convincing.