How would I go about making a good Space Skybox?

[Voideye]

The thread title states it. I've tried for a good week trying to make a space skybox and it always turns out horribly.. I hate using other people's textures and I would like to know if there is a good way to actually make a good looking Space Skybox? I've followed Photoshop tutorials and I haven't gotten the results I want. (The results I want are a vibrant but still cold space. A planet, some stars, and a nebula or two.) Could I get some advice or tips on making a good space skybox?

Thanks for any and all help.

[theCommie]

Have you used any of Greg Martin's tutorials on space?

Star Field
Planet

Here's a nebula one (heavy on brushes) different person:

http://img153.imageshack.us/img153/1821 ... tut5oe.jpg

[Voideye]

That does help. But I encountered another problem.. The skybox is incredibly low-res and I can't seem to get the images to flow correctly as a skybox. Every side has an edge.

[theCommie]

This is the best method I have come up with in my experiments with seamless skyboxes:

This is an example result in action.

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You'll need this tiny program; it has a set of panorama-editing functions that we'll want to use. (Because a skybox is essentially a cut-up panorama.)

You'll also want to have an abstract brush on hand when you have to mask or clone-stamp; I use this one. (Unless you're using photo reference (like me, in this case), and since I'm guessing you're drawing all of this manually - you probably don't need this.)

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First, draw your space-scape; we will be converting this image into an equirectangular panorama - this means all six of your skybox faces are already contained within this image, so make it large and make sure the image conforms to a 2:1 width-to-height ratio (For example, mine is 4096x2048).



Offset the image (in Photoshop, Filter > Other > Offset, make sure Wrap Around is selected) by half its width to the right. (In my case, by 2048)



The fun part; clone-stamp/mask or draw on top of the seam in the middle of the image.



Offset the image again to return it to the previous view.

Next, save this file (reccomend .TGA) and open it in HDRShop. Click OK on the dialog box that appears; it doesn't concern us.

Go to Image > Panorama > Panoramic Transformations, you will get a new dialog box:



1) Set the Source Image format to Latitude/Longitude.
2) Set the Destination Image format to be the same.
3) Set the Width and Height to your image's existing dimensions (check Source Image dimensions if unsure)
4) Select Arbitrary Rotation, then click on Settings; input 90 for the Z axis.
5) Uncheck Use Bilinear Interpolation.

Click OK; you will get an image with two prominent areas of distortion in the middle (right-click > Zoom Out to get a better view), like this:



If you still have Photoshop open, (in HDRShop) go to File > Edit in Image Editor, this will open the new image in Photoshop; proceed to stamp/mask away or draw on top of the distortions until happy with the result.



Save the file and open it in HDRShop once more. Again, go to Image > Panorama > Panoramic Transformations.



Pick Latitude/Longitude as the Source Image format, but this time, however, pick Cubic Environment as the Destination Image format. Now, depending on the resolution you want for your skybox faces to be, input one of the following for the Width:

1536 - for skybox faces that are 512x512
3072 - for 1024x1024 (this is the one I'll use)
6144 - for 2048x2048 (not recommended unless your source image is HUGE.)

Finally, click OK. You should now get vertical cross cubemap configuration which you can cut up into six images and convert to a seamless skybox!

[Major Banter]

Fuck me Commie, that's brilliant!

[trcc]

the name of the program confuse me. Is this a simpler tutorial on how to make HDR skyboxes or it's only LDR?

[theCommie]

HDRShop's primary purpose is for HDR image creation; the above tutorial, however, merely uses a specific feature of the program for manipulating panoramas, which just happens to be useful for the purposes of this topic. So no, this isn't a tutorial for HDR skyboxes - it will output an LDR cubemap. For the HDR tutorial, go here.

[trcc]

Cool, thanks.

[arieas]

Wow! That is a great guide, I have never bothered with nebulas background just plain white stars, could never figure out to go about wrapping and seaming a space skybox.

There will be a present in your bed tonight.