Rendering Great Skies

[nisus]

Hi all,

 

Since the tips on grass are really evolving well, maybe we could share some techniques about good skies too.

 

Why do you prefer a bitmap, a gradient, a skydome or even something else?

 

rgds

 

nisus

[Wolf]

i have a great SLR camera that i take out on most sunny days, and have taken a heap of 360 degree photos, and stitched them together in photoshop, then map it onto a hemisphere.

i find a picture of the real thing to be essential in realism. its also really good when you have reflections, to have a proper 3d sky, not just a background.

 

heres a little tip for you all......

 

i have to create a sky in most scenes i make,

so rather than making it again and again, i have made a little script for it...

 

dont freak out...no programming involved

 

all you do is open your maxscript listener

(bottom left) by right clicking on it and choose open listener window,

goto macrorecorder and choose enable, and minimize it out of the way

 

now create a sphere

type .5 in hemisphere

add a normal modifier

flip normals (so you can see the sphere from the inside)

add a uvw map

make it cylindrical

choose fit

 

maximize your listener again, and you should now see a whole heap of code in there

just select it all....and drag it to a toolbar

 

and you now have a button that makes a skysphere

 

you can model entire scenes this way and turn it into a button.

also good to study the code it generated, so you get to learn a little maxscript,

and get to know whats going on under the hood.

 

now...lets create a "Make Shrek" button

[PixelJockey]

Here is an article on creating an HDRI image from a fisheye photo. Although the article is an HDRI technique you can still use it to create hemi/spherical environment maps. I haven't tried this myself since I don't have a fisheye lens, but it's really tempting me to sniff around ebay for one.

 

From Fisheye to a HDR

[nisus]

Hi lads,

 

Although I use skydomes all the time, I am not very happy with most of the results.

 

Okay, skydomes are great for reflections, but that's about it in my opinion.

 

For stills some of my problems can be tweekened and although not all artifacts can be removed the results can be concinving. Animation tells another story...

 

The first main problem I encounter is that it looks flat and artificial. Most of the times I think the colors in these skydomes are to hard and to saturated. This problem can ofcourse be corrected by using specially prepared textured, but I don't see these things in productions often.

Adding a gradient from the horizon to the top can add realism, but the clouds still are on the same plane instead.

 

As producing a good bitmap is often a skipped proces, the idea of moving clouds by using a serie of animated bitmaps is a totally wacko.

And still the effect is amazing, especially if clouds move over each other in seperate layers.

 

This result can be achieved by using several flat skydomes (Xform scaled using the same center) and animating them - rotating or changing parameters -afterwards.

 

I usually use 4 layers myself:

- a complex background color gradient map:

I add a gradient from horizon to main sky color (mask) on top of a gradient from south to north

- distant clouds:

I make a color map and add non-uniform scaled opacity noise to create a few long streakes

- clouds middle-range:

same technique as the distant clouds, but I change the direction and look (color, shape, amount, etc.) of the streaks.

- nearby clouds:

again the same technique but i try to simulate puffy clouds this time.

 

To animate these clouds you can change mapping parameters, noise phase or size, rotate the domes and so on...

 

The results are often great and very subtle, but sometimes they too lack believe in animations because one easily detects the dome.

 

My second main problem addresses this "defined world instead of open air"-feeling: perspective!

Clouds too are subjected to the rules of perspective (they look much smaller in the distanve) but this cannot be accomplished by using skydomes. Eventually you can make a perfect map simulating depth, but by rotating your camera you'll give it away because you miss the real distance.

I have only seen one remarkable solution to this perspective problem so far. It is the technique used by Francois Mourlevat in his Vulcania-script.

 

Basicly Francois maps a cloud map (diffuse color and noise opacity-map) to a very large plane and adds a distant fog (same color of clouds) to hide the seem at the horizion.

Animating the offset and phase generates extremely realistic moving clouds.

If you extend this to several planes at different heights you can really boost the look of your animations a lot!

 

rgds

 

nisus

 

You can download the script at this location

http://www.scriptspot.com/download.asp?ID=38

 

Description: Vulcania is a generator of landscapes entirely integrated to max providing a help to the creation of natural environments. It makes it possible to manage the reliefs and the water levels, the ciels and the effects atmosphetic of fog, the horizon and the sun, the natural materials of the grounds. It is built on the principle of using only the tools available in the standard version of max.

[nisus]

Hi lads,

 

Anyone else got an idea to render great skies?

rgds

 

nisus

[Jeff Mottle]

Reposted for DelfoZ:

 

here antoher very good tip to create a Sky dome textures & easy . Only need 360° pics.

"Producing Polar Panoramas"

 

--------------------

Diseño en Movimiento

Arq. Carlos Portillo

http://www.delfoz.n3.net

[nisus]

Tnx Delfoz,

 

Veru strange but funny technique

Anyone else has a good idea for great skies?

Any DNT-users here?

 

nisus

[nisus]

Hi all,

 

Actually I am suprised by the very few different possibilities of rendering skies.

 

Does anyone uses DNT (digital nature tools)?

 

Anyone remembers 4E (four elements) on max r1 and r2?

 

rgds

 

nisus

[kid]

I use Vue D Esprit to render out 360 degree pano skies. I got version 2 free on a Compter Arts mag a few years ago. I usually render them out at 4000x1000 pixels then just stick em in Max environment as a spherical map. Here is a low res example

 

EDIT

Just an ani test I did a while ago Lowres Test ~560Kb Indeo Video 5 codec

 

[ June 01, 2002, 10:29 PM: Message edited by: kid ]

[nisus]

Hi Kid,

 

Looks nice... Great to see another CA-reader here

 

nisus

[samp]

Originally posted by kid:

I use Vue D Esprit to render out 360 degree pano skies. I got version 2 free on a Compter Arts mag a few years ago. I usually render them out at 4000x1000 pixels then just stick em in Max environment as a spherical map. Here is a low res example

 

EDIT

Just an ani test I did a while ago Lowres Test ~560Kb Indeo Video 5 codec

I didn't know that this was possible !?!

So I could just make my own 360° skies in Vue D Esprit ?

I have to get that program from under the dust again

[nisus]

Here is another tip on great skies: http://www.afterworks.com/DSBfirst.htm

 

rgds

 

nisus

[TAKA]

I use Bryce 5 for rendering skies

also great for generating panoramic images.

 

what's great about it is u can use multiple layers of clouds at different hights, volumetric clouds, etc, mess with haze, fog...bla bla bla

 

I also use KPT6's sky effects (PS plugin) ....kinda similar to bryce but much simpler controls....also renders panoramic images......

 

that's it for great skies

[jasonkey]

I've just bought a 2MP digital camera and would like to use it for doing my own skies. It's not a really expensive one (Sony DSC-P31) so it doesn't accept lens attachments.

 

So, my question is how can I get panoramic skies with it? I've heard about using mirrored spheres, does anyone have any personal experience about how well that works ?

[unreal]

Hi!!

 

The best way in stills is to go with a real sky photo, taken at the right angle and then added in photoshop in order to change the brightness, contrast etc. to match the look of the image...

[csven]

for CG skies, i'm surprised no one's mentioned Terragen. skies are arguably what it does best.

[Ernest Burden III]

for CG skies, i'm surprised no one's mentioned Terragen. skies are arguably what it does best.

 

http://www.cgarchitect.com/vb/search.php?searchid=27591

[csven]

"Sorry - no matches. Please try some different terms."

[Ernest Burden III]

"Sorry - no matches. Please try some different terms."

 

OK, that's weird. I tested the link after I posted it. The system may use some dynamic something-or-other.

 

Use 'search', enter "Terragen" and it should return this thread, plus a number of other recent ones about terragen, or where the discussion was co=opted to that subject.

[csven]

i did a search already. returned MY post in this thread. and some old threads; but i wasn't commenting on those other, older threads. i was commenting on this thread and no one mentioning it here. especially since the programmer has been continuing development on the program and made some recent updates/comments regarding it on his site. hence MY surprise.

 

that's all.

[Troy]

I have a 8.0 MP sony still cam that I'm about to go take some pics of the beautiful sky we have out there today. I set it up on a tripod in the middle of a farm field (one of the only benefits of being here in Indiana) shoot so i just get the horizon at the bottom of the image and then rotate the cam around making sure to overlap the shots. Then I stitch it together using a program called photovista. You can do it in photoshop as well. I just stumbled across this program and became lazy. I just map that onto a skydome. Although I've always been interested in making some middle ground clouds to give it more depth.

[nosnarb]

anyone know how these moving clouds were done? I know the animation was done in viz.

 

http://arch.ou.edu/arch/5023/f03/le6174/LES.HTM

http://arch.ou.edu/arch/5023/f03/le6174/LET.HTM

http://arch.ou.edu/arch/5023/f03/le6174/LER.HTM

http://arch.ou.edu/arch/5023/f03/le6174/LEA.HTM

[Ricardo Eloy]

Those can be either a procedural map applied to a plane or sphere with oppacity or volumetric clouds (dunno if Viz can create volumetric objects, though).

[mbr]

Here's some ideas:

 

http://www.turbosquid.com/FullPreview/Index.cfm/ID/228330

 

http://www.turbosquid.com/FullPreview/index.cfm/ID/195217

 

I think this area will develop fairly quickly. Dreamscape, from what I gather, is pretty great, just one of those '1000 options to learn' deals.

 

 

 

Personally, I am going to give Terragen a go, considering it's free for now.

[Adrian Bold]

Hi lads,

 

Anyone else got an idea to render great skies?

rgds

 

nisus

 

Amazing how technology can change. While we used to use a combination of skydomes for reflection maps, HDR for lighting and various methods for a colour background pass, We now use Vue6 xstream for most skies (and vegetation of course) and integrate with Maya.

 

We've had to create a few scripts inhouse to make this process more plausible but it works well with HDR, making believeable environmental backgrounds and no need to change methods whether outputting to Still or Animated media.