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How do you get a sky background?
About Truespace Archives
These pages are a copy of the official truespace forums prior to their removal somewhere around 2011.
They are retained here for archive purposes only.
How do you get a sky background? // New Users
Post by MountEtna // Oct 31, 2008, 8:34am
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MountEtna
Total Posts: 6
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For instance a blue sky with fair-weather cumulus - something like that? So far all I've managed to get is that uniform grey - not inspiring! The manual refers to infinite lights and skylights but they don't seem to make any difference at present. For instance I can't seem to activate the 'Intermediate' between 'overcast' and 'clear sky' control. And even if it's clear sky the render doesn't give a graded clear sky - just the unifor grey screen background.
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By way of comparison the package I used to use years ago ('Imagine' from Impulse Inc for the Commodore Amiga) would give you at least a graded sky background. You set for instance light blue at the horizon and dark blue at the zenith and the 'sky' would be shaded accordingly. It was dead easy to set up as I remember. To quote its manual (which I still possess) you went to Global (settings), Horizon RGB, +Zenith RGB, -Zenigh RGB and Sky Blending. The user would set all these values via one dialogue box simply by typing them in.
Imagine's manual also mentions a 'star field density' but then annoyingly adds 'This feature is not implemented with the current release of Imagine'. Tut, tut. Can you put a starry sky into a TrueSpace scene?
Imagine's manual also gives a useful table of refractive indices for standard materials or gemstones which I reproduce here for general info, not having found an equivalent in the Truespace electronic manual. Most users may already know these figures but in case some readers don't here they are:
Glass 1.66
Crystal 2.00
Water 1.33
Salt 1.54
Quartz 1.55
Emerald 1.57
Diamond 2.42
Don't get me wrong - TrueSpace 7.6 is obviously streets ahead of Imagine (being 2008 rather than 1990 and designed for GHz rather than MHz processors) and I'm only just beginning to uncover its potential. For instance scenes that would take hours to render in 1990 take minutes on a fairly bog-standard laptop (well, 2Gb RAM) in 2008. I'll also be able actually to implement things I could only dream about 18 years ago (24-bit colour for a start - the Amiga used an ingenious but non-standard 12-bit system). I'm sure this query re a sky background has a straightforward answer somewhere - just a matter of finding it!
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Just out of curiosity does anyone know what's happened to Impulse Inc? I think that for its time Imagine was a good product: one excellent feature was the ability to place points on the screen by typing co-ordinates, then joining the dots. This made mathematical curves (and aesthetically pleasing derived objects via Lathe etc) extremely easy to implement. The manual gives an address in Minneapolis-St Paul. I tried Googling for it but got 'page unavailable' at the suggested link (called 'Coolfun').
I know I'm still signing in as a 'newbie' but time for pursuing TrueSpace is a bit limited. I have a good window at present. |
Post by TomG // Oct 31, 2008, 9:02am
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TomG
Total Posts: 3397
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The skylight is just intended to cast light into the scene, and will not generate a sky background.
How you do that is actually open to several solutions. First, you can use a sky dome, an actual physical object that surrounds the scene, usually a sphere or hemisphere or sometimes a cube. You paint it with a sky texture, and ensure it renders double sided (since you are inside it), and there you go.
Another approach, since you are using the Model side if you are using skylights etc, is to use the IBL. It in effect is a ring of lights that can have a background associated with it - it actually works like having a virtual invisible sphere, so is the same in some ways as the skydome, only it has lights associated with it (the lights in the resulting array take their color from that point in the image).
Or you can use HDRI. The background image here them acts as an "infinite"sky dome, you can't move outside it like you can a sky dome or IBL. You can get some distortions in the image though, so sometimes it works better to go for the more old fashioned solutions like sky domes.
If working in the Model side, there used to be some plug-ins that did skies, which may be findable somewhere, though I am not sure on that.
Finally (or possibly finally, there may well be other options I've missed!), there are some clever shaders out there, I had an "infinite sky" shader for ShaderLab, you created a cube around the scene, but it calculated clouds procedurally on a "virtual plane" that it raycast onto from the ray intercepting the cube surface etc. There were procedural star shaders too, I had one for ShaderLab, there were others I am sure for Shader Magic and Simbiont. You can also use skydomes and starry sky textures of course, as well as cloudy sky textures.
So, a lot of ways this can be done!
HTH!
Tom |
Post by spacekdet // Oct 31, 2008, 2:16pm
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spacekdet
Total Posts: 1360
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I never miss a chance to trot out this old horse. (http://www.spacekdet.com/tutorials/skydome/) |
Post by mrbones // Oct 31, 2008, 6:17pm
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mrbones
Total Posts: 1280
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http://forums1.caligari.com/truespace/showthread.php?t=6937
I remeber seeing a nice constellation starry sky object at the scriptor meeting.. Not sure if its available yet. |
Post by transient // Oct 31, 2008, 8:05pm
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transient
Total Posts: 977
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I had an "infinite sky" shader for ShaderLab, you created a cube around the scene, but it calculated clouds procedurally on a "virtual plane" that it raycast onto from the ray intercepting the cube surface etc.
That's a really decent shader for quick sky backgrounds, thanks for the tip. :)
There's also infinity 2 which you can download from emmanuel's plug-in site (http://emmanuel.asset.free.fr/tsxarchive/index.htm). It's more complicated than the other solutions in this thread, but it is extremely versatile. |
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