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CLOSE-UP
ASTEROID RING IN VUE
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A common feature of space scenes, is an asteroid ring orbiting
a planet.
Now, if you are making a close-up scene, you do not need the whole
ring! ;) Remember, that everything in a scene costs "resources",
if you use a massive ring object full of hundreds of thousands
of rock objects in an ecosystem, that's a waste of resources,
if you can't see most of the ring.
Also, you cannot adjust it so easily for your small section of
scene: it's a whacking great ring, and the resource count can
slow things up.
However, there's an easier way to do it ;) Note: this does require
the use of a 3D modelling package if you want precision, but there
is a work around with just using Vue and a 2D paint package. Since
I'm so nice, I've provideed you with a
freebie 3D ribbon object to start from, though: hey, it's
Christmas! :p
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ASTEROID SUNRISE
an image where i used the following technique to create the
asteroid ring
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This technique uses a 3D mesh "ribbon", to form the
object on which an ecosystem of rocks will be created. The curvature
gives a nice sense of perspective and distance as it curves
away into the background.
Now, I'll try and explain how I created that in
Rhino3D and a possible Vue creation method, other modelling
packages can certainly make them too, but all use different
methods.
In Rhino3D, I created a cylinder, I "Extracted"
all the surfaces, deleted the top and bottom of the cylinder.
Then I used a cube to split off and remove most of the outside
ring of the cylinder, leaving me with an arc, like the outside
of a tin can, split. I exported this as an .obj file, and imported
into Vue.
There is a way to create such in Vue, but less
precisely: in a 2D paint package, make a square image, say 1000x1000
pixels, apply a gradient across it, going from black, to white
in the middle, to black at the other end. Save the image out
(prefferably as 16 bit .tif or .tga, which allows more colours,
and thus, more precision).
In Vue, apply this image to a Terrain ("Picture")
to create a curving terrain, make the terrain about 1024x1024
size.
Edt the terrian, click the TERRAIN OPTIONS button, drag down
and select SKIN ONLY, this means only the surface of the terrain
object will exist.
You should now have a curving, flat terrain surface! ;) (Note
you may need to invert the image, as Vue usually reverses how
black and white should work, sigh).
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CURVE MESHES "RIBBONS" INSIDE VUE,
SHOWING THE ECOSYSTEM ON IT.
I made two versions of the object, and found one worked better
than the other, as I "UV mapped" the final one, lower
and broader one, better.
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After scaling the ribbon object to suit your scene's requirement,
you need to make it invisible, as you don't want it to be seen
in the actual render.
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MAKING RIBBON OBJECT INVIISIBLE
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Next, add a new material layer, this will be the
ecosystem with rocks. Make the underlying material be
"Invisible" same as the ribbon. It works better if
the ecosystem is on a seperate layer, from my experiments.
Driving the ecosystem, so as to create a believeable
asteroid field, takes a bit of tweaking in the material editor,
sorry! ;)
Name your new layer ROCKS, or whatever, select
"Ecosystem" as Type. This is where it gets complicated,
but not too complicated, don't worry, hey, it has to make sense
to my "386" brain, so should be ok for you! :D
The plan is to make the asteroid rocks vary in
size and distance from the base ribbon object, in a random size
amount, but within a certain limit of distance from the object.
Note that these settings will vary depending on your scene!
But are a good start.
Also important to note is I built my scene's ship
model to exact real size, so it was quite large, and the asteroid
field was scaled for that, but I ended up scalling the ship
down a lot to look better...it's always a case of tweaking to
get things looking good!
Took me a lot of fiddling and tweaking to get
these settings, you of course can try other ways and amounts.
There are two required systems needed: one for
density of the asteroid field, the other for how far from the
ribbon object they extend.
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DENSITY FUNCTION OF THE ROCKS LAYER
Note: select "Proportional to size of
instance"
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CLOSE UP OF DENSITY FUNCTION
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OVER ALL ECOSYSTEM DENSITY AND OFFSET FUNCTIONS
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DENSITY VALUE FUNCTION
Scale set large as these asteroids are going
to be enormous lumps of rock, as the ship is close to them.
If your ship is larger or further away, make the scale smaller
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DENSITY: ADVANCED TURULENCE SETTING
Add for more variation, connected to ORIGIN of Simple Fractal
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DENSITY BRIGHTNESS CONTRAST FUNCTION
To boost density, connected to GAIN input of
Simple Fractal
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DENSITY SIMPLE FRACTION FUNCTION
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DENSITY FILTER FUNCTION
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DENSITY MULTIPLY FUNCTION
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OFFSET FROM SURFACE FUNCTION SIMPLE FRACTAL
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OFFSET FROM SURFACE FUNCTION
Note large Multiply number is required
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SIDE-ON VIEW OF THE PARTIAL ASTEROID RING
PS, note Vue can let you make high altittude planet renders,
subject for another tutorial, I guess! ;)
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Note: thanks to various folks over the years, who've worked on
asteroid fields in Vue, on Renderosity and other sites :)
Back in 2005, "Phoul" (Phillipe Bouyer) posted on such
on Renderosity and me and Wabe and Phoul beavered away on how
to get asteroid fields working.
http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2295527&page=1
Fun! :)
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I hope you find this of use! :)
All original art, writing on this site, copyright of
Steven James, "Silverblade the Enchanter" ©2010
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