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Starburst
Starburst
Comments: 6
spektyr

21.11.2018, 09:38








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Cloud Cover
Cloud Cover

            

Cloud Cover
Description: Experimenting with Voluemtrics and IBL. Sunlight provided by a radial.

Scout ship model found here:
http://www.renderosity.com/mod/freestuff/index.php?user_id=121821

Feedback is appreciated. Thanks all for your time.
Added by: rashadcarter1
Keywords: rashadcarter1, bryce6.1, IBL, volumetrics, aviation
Date: 07.17.2009 07:20
Hits: 8704
Downloads: 1
Rating: 5.00 (2 Vote(s))
File size: 635.3 KB
Previous image: Trafalgar2a
Next image: Dead in the Water



Author: Comment:
adrian
Member

Join Date: 07.28.2004
Comments: 105
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Wow, amezing clouds!
I cant believe bryce is capable of this.
Wonderful piece of work Rashad!
07.17.2009 09:01 Offline adrian adsl466849 at tiscali.nl
richter
Member

Join Date: 04.15.2004
Comments: 1097
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That's what I call an unbeatable 5er for volumetrics, Rashad! Because of how the cloud layers look, I'd swear this was made in Vue, which I believe is a great deal of presenting and simulating in Bryce. I couldn't have done it better. I'm curious how many spheres (random distributed I guess) you used and what was the rendertime?

I will not be Richter if I don't find anything to quibble about, will I :)) So.. the flying model has a really nice design, but it's too artificially reflective and I can see some normals-issue facets. If you import it in Maya (or wings even) you could smooth it 1 or 2 iterations.
07.18.2009 09:41 Offline richter richter at cold-may.com
Horo
Admin

Join Date: 05.26.2004
Comments: 4464
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Well, if I wouldn't know Rashad, I'd say that sky is from a photograph. Very very nice and certainly worth a fiver. The ground looks very good and natural, too. The scout ships came as a second thought, I guess - to give an "excuse" for the cloudy sky. They just don't fit as nicely into the composition as is the case with other compositions by you, where I get the impression everything was thought out before you started building it. But the fiver you get anyway.
07.18.2009 21:30 Offline Horo h.-r.h.wernli at bluewin.ch https://www.horo.ch/
connorzelinsky
Member

Join Date: 03.30.2007
Comments: 394
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That is by far the best sky I have seen created in Bryce. If I may ask, how did you do it?
07.19.2009 16:39 Offline connorzelinsky connorz16 at gmail.com
rashadcarter1
Admin

Join Date: 06.04.2006
Comments: 2622
-

First, thanks so much to Adrian, Horo, Richter, and Connor for the feedback, seems difficult to get feedback sometimes.

Horo, you are surely correct, the clouds were my real goal and the ships were added as an after thought, more of a compositional focus to ground the image a bit. Richter, I did observe the model facetting and should have fixed it, but generally I tend to avoid altering models made by other people. In this case that was a bad idea.

This scene was developed from within a volumetric cloud plane. I had to test many camera positions before finding an open area for the camera to view the contents of the plane. Took over a week to find this camera shot. I am working on photorealistic clouds that go beyond any previous approaches, so far I feel good about this. Soon I will prepare a tutorial.

Generally, bryce can create volumetric models that are equal or better than Vue, Carrara, terragen. But Bryce's lack of full GI lighting tools means that Bryce clouds are usually poorly lit in terms of realism, which is highly unfortunate and leads to a great deal of fakeness.

My goal was to test a detailed Bryce volumetric model when lit under a realistically faked GI, provided by a special gradient skylight hdri I created for outdoor scenes. I wanted a scene that looked more like Vue than Bryce and it was the lighting that was they key. Not to take anything away from cameras and true hdri, but there is no physical way possible to find a real world situation that is essentially isolated enough to capture the radiance potential of the sky without contamination from environmental issues such as the sun, clouds, ground, etc.. Only 2d gradients who are drawn based upon a logical theoretical sky brightness output can light a cloud and an overall outdoor scenario like this one. More on that later.

Bryce has some problems right now where a uniform hdri does not produce uniform light output. This makes creating reliable skylight gradients very challenging when it should be the easiest thing in the world to accomplish. As soon as the developers fix this, I plan to produce skylight hdri with the sole purpose of providing convincing skylight for Bryce renders.

More on skylight gradient images and why they work better than true hdri pictures of the sky:
Sunlight and skylight are not the same thing at all and should each be addressed individually for optimal control. At one time I thought a single hdri could provide both of these effects convincingly. Each must be given its own time and attention to accuracy. Skylight is much trickier and much more essential for landscapes than it appears so many take it for granted. I now use IBL for one purpose, diffuse multidirectional skylight only. Skylight is based upon the physics of light scattering within a medium of air molecules at different altitudes. So a realistic skylight gradient has to be based upon air thickness at different altitudes without clouds or sunlight, not literal pictures of the sky which are surely contaminated by the sun position and the environment, and that is why pictures of the real sky are not useful for skylight in Bryce, in my opinion. Since the air is always thickest near the horizon, the sky outputs much more light energy along the horizon and less and less light at higher thinner altitudes. This is true regardless of the time of day, the horizon always outputs much more light energy by comparison than the top of the skydome where air is thinnest. This is a skylight gradient secret many fail to observe. My skylight hdri is black at the dome summit and progresses to full white along the horizon, all with a sky blue tint. The resulting skylight has blown my mind with the accuracy and realism. Only after I realized the horizon was the brightest part of the sky was I able to produce a truly realisitc skylight gradient for use in this image and other recent images.

Quality was set to 16. Render time was roughly 12 hours, that would be 2 days on the average dual core. This is a special cloud mat not yet released to anyone. I need to test it further before publishing the material and the necessary lighting tutorial.

Thanks again to all 4 of you for the feedback!
07.20.2009 17:36 Offline rashadcarter1 rashadcarter1 at aol.com
bullit35744
Member

Join Date: 10.22.2008
Comments: 394
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Beautiful Rashad!!!
07.20.2009 19:59 Offline bullit35744 https://sites.google.com/site/bullit35744
boekenwuurm
Member

Join Date: 04.02.2009
Comments: 22
-

Wow rashad, looks good! Much better then my attempts to realistic clouds (they got the complement that they had a cartoony look, with they have.)

May I ask, is the camera placed in the cloud plane? and is the ground plane far beneath the cloud plane? If I look at it, the mountains at the bottom tent to stick through the clouds, but the ground seems to not much lower. This could be an illusion, or a misjudgement from me (I've never bin higher then 50 m above the ground, so never looked inside clouds)

I would also be interested what happens when you put one of the ships in the clouds? Does it give problems like when intersecting two volumeric spheres?

I like the lighting of the clouds, very realistic. Is the grainy edge of the lower density clouds the result of compression or a characteristic of bryce clouds? I've seen it at my own experiments much clearer then here.

At last, I want to say the same as everybody here: beautiful!
07.20.2009 22:10 Offline boekenwuurm boekenwuurm at gmail.com
rashadcarter1
Admin

Join Date: 06.04.2006
Comments: 2622
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Thanks Trish, and thanks Boekenwuurm.

You raise interesting questions Beokenwuurm. Very insighful, I like the way you think.

Creating a sense of height is not always easy, especially with the peculiarities of the outdated Bryce skylab.

Visibility from above when looking down can be a tricky calculation. I assume from research that the Earth atmosphere is roughly 35-50 miles thick. 35 miles of air seems like alot, but it really isn't in terms of scattering of light. When standing at sea level looking forward one might look through hundreds of miles of air, thus the obscurity of ground level haze. They say the average jet plane flies above 70% of the total atmosphere. Anyhow, satellites from space can peer down through the atmosphere to capture images of the planet surface with near perfect clarity on clear days. I assume there is software helping to account for atmospheric issues, but generally when looking downward from above thick haze should not be too much of a factor.

Which means that I cannot rely on haze to indicate distance and scale as I normally would. It took me a while to figure out how to get the cloud plane and haze to work together realistically. What I should have done was to add a few more objects on the ground as visual scaling clues. If one can imagine the true height of these clouds, they are not a thin plane but a very tall plane.
07.21.2009 21:36 Offline rashadcarter1 rashadcarter1 at aol.com
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