rendering a skybox...

ok, this is getting aggervating. after much trial and error, I found that setting the camera lens to 15.94 yields a perfect square, so you can render front, top, down, left, right, and back seamlessly by rotating the camera 90* each time.

so whats the problem? Well…easiest just to show you.

http://www.cdom.net/A2597/WTFSkybox.jpg

as you can see, the seams line up perfectly (It looks funky, thats due to it not being mapped to a cube as it will be in UT2k4, in game, it looks round)

However the top is colored differently, and suddenly the clouds are insanely bump mapped.

WHY?!? The lighting is the same, all that has changed is the camera orientation.
Is there any way to fix this? HELP!

first, a lens of 16.0 is exactly 90 degrees
[well, you need a square aspect and stuff]

“insanely bump mapped”

are you trying to make a cubemap for ut2k4 in blender?

I bet the problem is that you have a specularity on your surface, and as the camera is turned around things change in their lighting. Or, something like that, see if you can get your around sides using the panorama settings, and simply have a second camera for straight up.
http://www.blender.org/modules/documentation/htmlI/x8296.html
[you’ll want to use the lens of 16 part because when cut up and folded around a cube it will work correctly]

the other issue you may have is if you use seperate images for the sky cube, the seam between them will probably become visible unless there is an option to turn off texture repeating for those faces.

my solution would be to not use seperate textures, but instead to make a cubemap [which would only work on some hardware, and I am not sure the unreal enine supports it], or to combine things into one texture and use another skybox shape [because cubes aren’t easy to uvmap well]

for example, an octohedron.

[bunch of info on that here, though probably still not enough]
http://www.elysiun.com/forum/viewtopic.php?t=28678

ok, I fixed the bumpmapping just by removing it. not my first option, but eh…

the latter, matching the coloring, I fear will be much much harder. The freshnell effect is light based, so, since the camera is turning…sigh

I’ll try with two cameras for a panorama, maybe that will work…

but I have to get the 6 angles for UT2k4. Up, Down, Front, Back, Left, Right…

why?

iirc the skybox is just a regular brush flagged as skybox

and also iirc, you can import meshes as brushes

really [I dunno if it will be seamless either], if you don’t want to worry too much about positioning cameras you could just add an empty and render an envmap from it, then save it [and cut it up and rotate things as necescary in your preferred image app]

however, things really ought to be seamless on an envmap, they often are not. I haven’t seen problems with panoramic rendering [I think I heard halos had problems though]… I dunno

panoramic rendering works perfectly for front, sides, and back, but up and down? Nope, not at all…the lighting changes to much. Sigh

I suppose I’ll improvise, and make the planets further back so they fit entirely on the top/front/bottom sides…but I was hoping to have the camera quite close. :frowning:

And if you parent all your lights to the camera?

%<

then the back of the planets that are supposed to be in the shadow, are full bright. :smiley:

So out of interest, is this a bug in the renderer? or just a natural result of the way that a curved view is projected onto the plane of the camera lens…

I don’t know how the skybox format works, but have you tried rendering rendering out an environment map taken from the centre of your scene? Maybe you might need to change the layout of the various ‘planes’ in an image editor in post, but it might work.

It does work. It’s easy.

Nope, Envmap doesn’t work either. :frowning:
The lighting just doesn’t match up. And also since I need each side to be 1024x1024, it’s too small as well.

maybe this will help, the packed blend file.

http://www.cdom.net/A2597/skybox.rar

That has the envmap in there as well, soo, you might want to turn that off if you don’t intend to use it.

(And thanks thus far for all the suggestions! :smiley: )

I’ll figure this out for you as soon as possible; Right now my computer is in the middle of rendering out a huge file, so Im limited to what I can do :smiley:

Hopefully I can sort this for you, I have a few ideas.

thank you VERY much man! :slight_smile:

(As you may have guessed, I’ve been banging my head over this for some time…)

Ok, done it.

I’ve provided an example file for you to follow, similar to the file you posted above, but since I found the settings in your file a bit hard to understand, I started from scratch.

oh yeah, about the atmosphere, you do know that you can use colour ramps to simulate them now? The advantage of using this method is that you can actually create an animation now without your atmosphere going everywhere :smiley:

Quick expample

http://members.charnwoodarts.com/Dave/skybox/ramp_example.jpg

(bad example I know)

Anyway, here is the file:

http://members.charnwoodarts.com/Dave/skybox/skybox_example.zip

Instructions are included.

Post processing the envmap:

once the envmap is rendered out, you will notice it looks like this:

http://members.charnwoodarts.com/Dave/skybox/blender_envmap.jpg

Note that the text is rotated the wrong way around, I set up this text in the example flie as a reference; Rotate the text the right way around and you know that your sigle cubefaces are correct. Like this:

http://members.charnwoodarts.com/Dave/skybox/cubecross.jpg

How? well basically I setup up photoshop’s grid to have a gridline every 512 pixels (the size of a single cubeface)

http://members.charnwoodarts.com/Dave/skybox/gridsetup.jpg

and made sure that I had “only” the snap to grid option selected.

http://members.charnwoodarts.com/Dave/skybox/showgrid.jpg

Then I used a fixed sized rectangular marquee tool set at 512x512:

http://members.charnwoodarts.com/Dave/skybox/rectangular_marquee.jpg

Then snapped to each of the cube faces, then copied and rotated each of the faces. Simple!

Heres a single cubeface rotated the right way:

http://members.charnwoodarts.com/Dave/skybox/bottom_cubeface.jpg

(Crush voice from Finding Nemo)

YOU SO TOTALLY ROCK MAN!

(/crush)

The ramp shader fixes it perfectly! That is GREAT man! (Mind keeping that file up for ohhh…6 more hours, I’m stuck on campus PCs at the moment, no way to get that home with me right now. :smiley:

Thanks man!!! :o :smiley:

allright got the file. nice Hoth map BTW. :slight_smile: