Software for generating sky boxes/spheres ?

TorQue[MoD]

Back in the day, people used to use either Bryce or a program called Sky Paint to create skyboxes/spheres. Since neither program exists anymore, I'm wondering if there's an alternative that anyone knows about. Hopefully, a modern alternative that allows the creation of flow maps for animation or something similar.

Thanks!

gnoop

Forget about boxes . it's an ancient thing  from a time when evry triangle was on count.  As of the skydomes  I used Hugin  last time  I did it.   Decade ago actually .     The main  problem with a sky is not how to do it but rather where to shoot it .    I recall I had my own list of abandoned places with broken locks to access roofs.

As of  flow maps  I am affraid you would have to do it manually  in any image editor  that support  color change depending on stroke direction.    You do a stroke, sample the color and then fill a shifting area with it.   That part could be done in Substance Designer too, It also has a useful node to rotate normal map vectors  to necessary angle globally  if your initial stroke color is not exactly right

 Then  you can set it up an animation  in any 3d package really.   By playing with UV inputs in shader editors.  

   I recall some Forza version  did it  that way probably   but I have no idea how exactly .  Not sure they used a flow mp at all. maybe just some geo morphing .

TorQue[MoD]

gnoop said:

Forget about boxes . it's an ancient thing  from a time when evry triangle was on count.  As of the skydomes  I used Hugin  last time  I did it.   Decade ago actually .  

As of  flow maps  I am affraid you would have to do it manually  in any image editor  that support  color change depending on stroke direction.    You do a stroke, sample the color and then fill a shifting area with it.   That part could be done in Substance Designer too, It also has a useful node to rotate normal map vectors  to necessary angle globally  if your initial stroke color is not exactly right

 Then  you can set it up an animation  in any 3d package really.   By playing with UV inputs in shader editors.  

   I recall some Forza version  did it  that way probably   but I have no idea how exactly .  Not sure they used a flow mp at all. maybe just some geo morphing .

Thanks for the suggestion gnoop. I've never heard of Hugin so I'll give it a shot. I'm just working on a racing title where I want the skies to look pretty, but don't necessarily need volumetric clouds or anything more modern like that. I thought there has to be a more advanced piece of software by now for making sky spheres, but maybe not? I thought it's always nice to see the clouds moving while you're stationary, but maybe since it's a racing game, I'll just use an HDRI and call it a day? I like the extra little details though so thought it might be nice to have a separate cloud layer generated in a 3D program and then baked into a texture. 

TorQue[MoD]

Ooooh! I have heard of Hugin. I was more thinking of a piece of software for generating the skies procedurally, rather than a program for stitching together photos. 

gnoop

TorQue[MoD] said:

Ooooh! I have heard of Hugin. I was more thinking of a piece of software for generating the skies procedurally, rather than a program for stitching together photos. 

 

I used Terragen  decade ago  . To render a static sky texture I mean.   Have not updated it  for pretty a while.       Did it in Vue too  but it was a hellish experience.  I don't like Vue at all

As of HDRI  you can actually edit LDR  picture into HDR  one manually  in something like Affinity photo that has better 32 bit mode support than Photoshop.     Also Hugin  has no problem to build you HDR pano too.  You just have to shoot bracketed  series.     In fact Photoshop  have a good  panorama building script too . Fully automatic and HDR.   Easier than Hugin  nowadays  probably.

 Well , Affinity Photo too actually, you just  need mesh wrap  it to straight horizon line

   Any real thing would be always look better than any  procedural one IMO ( at least in my experience)   and Photoshop made a great advance with separating anything . Its AI is well trained for skies .

Besides  you usually need the sky  texture in pretty hires  and noise free.     Terragen took virtually days for me to render this   decade ago, hi res and noiseless+all the AOVs.    With modern AI noise suppressors and 64 core AMD  it might be better but I never tried. 

All defaullt cloud layers are so -so in Teragen  (  in version I have)  You have to spend pretty a while  going deeper into  node system  and master it .   

   It sometimes cool in one  frame sector  of a sky and totally artificial and unrealistic  in other half . So expect doing a lot of post compositing  and many renders.

Never looked  at Vue  since my Vue7 license but it still might be a choice too.

TorQue[MoD]

gnoop said:

TorQue[MoD] said:

Ooooh! I have heard of Hugin. I was more thinking of a piece of software for generating the skies procedurally, rather than a program for stitching together photos. 

 

I used Terragen  decade ago also . To render a static sky texture I mean.   Have not updated it  for pretty a while.    It has pano camera . 

As of HDRI  you can actually edit LDR  picture into HDR  one manually  in something like Affinity photo that has better 32 bit mode support than Photoshop.     But Hugin  has no problem to build you HDR pano too.  You just have to shoot bracketed  series.     Any real thing would be always looks better than any  procedural one IMO ( at least in my experience)   and Photoshop made a great progress with separating anything.

  Modern games   although use ray marching  volumetric  3d clouds  now . They are just a complex shader.   I bet you could do it in U4 editor but I'v never tried myself .

Yeah, UE4.25 + has volumetric clouds built-in now, and they're quite easy to generate, but it's expensive to render for a game where you're not really spending any useful amount of time actually in the sky. 

You might be right in regards to using photo sources. I should get a 360 degree camera and find someone with a tall building in the middle of the city :P 

I found this in my most recent google search and it's pretty cool so I thought I'd share... http://wwwtyro.github.io/space-3d/
If you turn off the stars it's a pretty good generated sky though a little too cloudy in every version. 

Eric Chadwick

Check out polyhaven for some nice free HDRI sky panos.

https://polyhaven.com/hdris/skies

gnoop

Those are  not very hires.   And spherical projection itself  supposes you are getting lots of pixels  everywhere except  an important  area of the sky  30 deg  over horizon line .  A part  of a sky you would see  from a car  most of a time.    it could turns very low res  there.  You need a pano of 16k pix  long and 8k hight at least   considering you are gonna  loose resolution un- warping all those horizon wobbles .    Especially if your game  is supposed to have long focus  cameras on replays

it's same issue with  360 deg two fish eye lenses cameras.   lack of resolution

Eric Chadwick

Is this for a game or not?

gnoop

Eric Chadwick said:

Is this for a game or not?

If a game is not a mobile one  and your  world  is like 3-5 pix /cm  texel density    you still need  a pretty hi res sky,    maybe  4196x4196  . it's roughly   16k  k  x 4k   if represented as a spherical projection stripe.   Still be blurry on long focus replay cameras but you can hide it with dof  kind of.

Eric Chadwick

A 4k sky map is very extravagant, your graphics engineers/tech artists are going to be pretty upset with you.

Layering is usually the way to go. Some tips here:

https://www.artstation.com/artwork/dqE21

https://80.lv/articles/creating-skyboxes-for-aaa-games/

gnoop

Yeah,  I  actually did  2k  ones  when we had static sky .    So maybe 4k is too much.    Still I doubt that layering approach  would be good  in a racing game.   Those layers never look real enough.   Maybe  in styled art  like WoW that would be ok or with a lot of mountains  obstructing distant sky areas  but not in big flat open spaces  racing tracks are usually.      Still it's possible choice for sure.

in my  history of racing games it had always been either a single texture or  two textures. One for distant sky stripe  packed as 4 uv islands  and a cap  usually  not so hi res.      Scrolling layers never looked real and always were kind of eye catchy .       Now it's ray marching  and honestly  I prefer static ones .

TorQue[MoD]

gnoop said:

Yeah,  I  actually did  2k  ones  when we had static sky .    So maybe 4k is too much.    Still I doubt that layering approach  would be good  in a racing game.   Those layers never look real enough.   Maybe  in styled art  like WoW that would be ok or with a lot of mountains  obstructing distant sky areas  but not in big flat open spaces  racing tracks are usually.      Still it's possible choice for sure.

in my  history of racing games it had always been either a single texture or  two textures. One for distant sky stripe  packed as 4 uv islands  and a cap  usually  not so hi res.      Scrolling layers never looked real and always were kind of eye catchy .       Now it's ray marching  and honestly  I prefer static ones .

When I'm doing a sky sphere, usually I just use a dome and squish the horizontal HDRI map into a square (so take a 16384 x 4096 and resize it to 4096x4096) and then run a polarize filter on it in Photoshop. 
Eric, why would a 4K skydome be so bad? It's a single texture loaded once. I'd have assumed most GPUs can handle the cost easy.

TorQue[MoD]

Eric Chadwick said:

A 4k sky map is very extravagant, your graphics engineers/tech artists are going to be pretty upset with you.

Layering is usually the way to go. Some tips here:

https://www.artstation.com/artwork/dqE21

https://80.lv/articles/creating-skyboxes-for-aaa-games/

Thanks for the links and for the HDRI link too

Eric Chadwick

Just think of all the other assets that need to be in memory too. GPU memory is at a premium, and that skybox is going to be seen all the time, so it can't be unloaded to make room for other things. Of course, YMMV, etc.etc.

gnoop

4 k texture  perhaps is too much really .  but  two 2k UDIM ones  I think would be perfectly ok  for modern texel density .      After all the sky is a half of a screen and pretty important visually and you don;t want to see something blurry next to your hi res world.   Especially that stripe of distant sky  over horizon line   which give  you  sky perspective impression.

   Layering approach  could let you to have something  moving slightly but not fully dynamic day/night cycle anyway   and doesn't help you with resolution issue really . You couldn't re-use layered cloud on other sky sectors due to totally diffrent lighting in those  sectors.    it works for some abstract  stylized  sky  IMO   irrelevant to illumination     but not  for something like  GTsport   skies  .   I tried.   

 

TorQue[MoD]

Eric Chadwick said:

Just think of all the other assets that need to be in memory too. GPU memory is at a premium, and that skybox is going to be seen all the time, so it can't be unloaded to make room for other things. Of course, YMMV, etc.etc.

Fair point. I just didn't think keeping a 4K texture on screen at all times was really a big deal. It's like what, 48mb out of 8GB of texture memory on a PS4/Xbone. I think even the switch has 4GB of video memory, doesn't it? That's why I figured 4K skybox isn't such a big deal. 

EGGO

May be you'll find useful this one browser-based flowmap generator here:
https://cables.gl/p/ntZfmv