Author Topic: Ray marching / "True sky" clouds  (Read 246 times)

Offline KirillK

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Ray marching / "True sky" clouds
« on: January 09, 2018, 01:42:41 PM »
Is there any possibility we would ever see ray marching clouds / GPU rendered ?
 I know in many games they look pretty low res and primitive  still somehow I feel the real-time nature  of them that allows more interactive setting and adjusting  sometimes helps to reach more natural impression than what I ever got with Terragen clouds which sometimes may look super cool in a specific frame but then,  60 degree aside  or  a few frames after it's nothing looking naturally any more.   So it always ends up into non stop adjusting then compositing, hand re-painting etc.     

I just hope that ray marching being not limited by a game fps requirement may be looking cool too.

Offline Artice-3d

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Re: Ray marching / "True sky" clouds
« Reply #1 on: January 09, 2018, 02:40:17 PM »
Actually i agree!!! Many games uses realtime volumetric clouds that look actually amazing and realtime like Simul True sky, something like this

https://www.youtube.com/watch?v=rGz2AW6hD7Y

And it's pretty easy in settings !!! I even don't get why software developers don't do anything semi realtime with higher quality, but for rendering 20 seconds not 2 hours!!!

Even unigine has beautiful skies realtime!!  They have even realtime best GI and reflections.. They looks like V-ray but rendered realtime!!

https://www.youtube.com/watch?v=tui5-x2i2zw

I know that raytracing is quiet expensive, but maybe hybrid methods do the magic = renders faster with stable quality :)

And by the way world creator 2 has realtime stuff too!!  :o ;D ;)
« Last Edit: January 09, 2018, 02:48:24 PM by Artice-3d »

Offline Matt

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Re: Ray marching / "True sky" clouds
« Reply #2 on: January 10, 2018, 03:06:09 PM »
Terragen clouds are rendered using ray marching. But they also use other techniques to improve the final quality (such as voxel caches and brute force secondary scattering). There are many other reasons why our clouds don't render as fast as "True Sky". We focus on maximising photorealism and providing many options for controlling the shapes of the clouds, so our code needs to be more complex and this takes longer to render. However, our reliance on the CPU rather than the GPU is certainly a big factor.

I think within the next couple of years we will spend some time to convert some of our cloud rendering code to the GPU, and I think this will allow us to do fully realtime interactive cloud editing.

Matt
Just because milk is white doesn't mean that clouds are made of milk.

Offline pokoy

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Re: Ray marching / "True sky" clouds
« Reply #3 on: January 10, 2018, 06:35:56 PM »
Matt - that sounds great, looking forward to any improvements. Although the new cloud model has made things a lot easier, they look way better now.

As for clouds not looking real anymore when you change POV - I have tons of reference images of different cloud types at different heights shot from a helicopter/jet for our internal usage. And what I've learned is that real clouds can look quite 'fake' under certain conditions, or just not as pretty as one would expect. I guess they can look as 'wrong' in TG as they can in real life. For a lot of these images, if I were to judge if they were rendered or real I'd say they were rendered and don't look 'good enough'.

With that said, the current voxel caching can make things hard to pin down (50 or 500 millions - where's the truth?) and with all the other parameters it can be a bit of a hit and miss sometimes. It surely would help to be able to render them faster when tweaking settings.

Offline penboack

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Re: Ray marching / "True sky" clouds
« Reply #4 on: January 10, 2018, 08:45:21 PM »
Well I looked at the TrueSky demos and I don't think that they look that good or realistic.
TG Clouds are far better.
It would be great to fully realtime interactive cloud editing in TG!

Offline KirillK

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Re: Ray marching / "True sky" clouds
« Reply #5 on: January 15, 2018, 11:44:57 AM »
  TG clouds definitely could look way more realistic for a certain specific frame or POV.  Still in general, from a ground based POV,  they often looks too surreal  and needs a lot of manual masking and re-compositing to hide it.   I bet that surreal impression is a kind of opposite side of  trying to give more variable cloud shape and nature than what Truesky and such do.

An ability to have a true real-time visual feedback is a key thing  imo since sometimes I see almost perfect clouds in preview window but after the final render  they turn surreal again.

Real time feedback is what makes Substance Designer so great for procedural textures, for example  and why people do so realistic materials there over other similar cpu limited softs which in fact may have better and more flexible options.


Offline agent_unawares

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Re: Ray marching / "True sky" clouds
« Reply #6 on: January 20, 2018, 05:53:28 PM »
I didn't find unigine convincing at all. The TrueSky clouds also didn't have too realistic edges, it almost looked like the clouds were made up of a torn paper collage, but 3D. But the way the light interacted with them was so pleasing to my eyes.

 

anything