Hi!

I've been trying to make a fast rendering asteroid field for the irtc animation
I'm working on (see my post on p.b.a). Anyway, I just came up with this and I'm
pleased with the result.

It rendered at 640x360 in 50 seconds on my pIII 550. Which is pretty fast!

The asteroids are created using 2 seperate effects:
- The nearby asteroids are a mesh object created in Wings3d, with an agate
normal map. There's only a hundred of these high detail ones, and probably only
about 30 of them can be seen in this shot.
- The distant ones are part of the sky sphere, and are drawn using a slightly
complex texture based on the crackle pigment. They appear lit because their
colouring uses

Anyway, the reason for my post is I want to know if this looks right to you.
Does it look like an asteroid field? Is it realistic or movie-style? (I'm not
sure how real ones compare to the ones I've seen in Star Wars!) Does nasa have
any photos? I couldn't find any good reference.

Cheers
--
Tek
http://www.evilsuperbrain.com

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Tek wrote:

> Anyway, the reason for my post is I want to know if this looks right to
> you. Does it look like an asteroid field? Is it realistic or movie-style?
> (I'm not sure how real ones compare to the ones I've seen in Star Wars!)
> Does nasa have any photos? I couldn't find any good reference.

Very nice, but I'm not so sure about the colors, perhaps they should be 
grayer? Also, I think that "in a real thing" the size distribution would be 
something like "inverse-exponential" ie. there are much much more small 
rocks than big ones. About realism, this is obviously movie-style. Real 
asteroid fiels (well, the one around Sol anyway ;) are actually very 
boring. Ours is so sparse that chances of seeing, much less hitting, an 
asteroid during a voyage through the belt are very slim. Probably nothing 
worth seeing comes even within 10 000 kms distance of the spacecraft.

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Definitely more grayness to them for realism.  Also, they should be much
smoother.  And in space, if you were in an asteroid field, you would not see
other asteroids nearby except as an occasional point of light moving very slowly
across the sky.
    Let me dig out some of my asteroid stuff and see how they look.  Hopefully I
have something worth posting.
    By the way, nice picture.

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip

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Johannes Dahlstrom <sad### [at] tkukoulufi> wrote in message
news:3e330ee1@news.povray.org...
> Very nice, but I'm not so sure about the colors, perhaps they should be
> grayer? Also, I think that "in a real thing" the size distribution would be
> something like "inverse-exponential" ie. there are much much more small
> rocks than big ones. About realism, this is obviously movie-style. Real
> asteroid fiels (well, the one around Sol anyway ;) are actually very
> boring. Ours is so sparse that chances of seeing, much less hitting, an
> asteroid during a voyage through the belt are very slim. Probably nothing
> worth seeing comes even within 10 000 kms distance of the spacecraft.

Well I've been looking online for some reference photos. The colour I picked, by
sheer chance, is almost identical to some asteroids in Star Wars! :) But yeah I
think they look too colourful.

Good suggestion about the size distribution, I hadn't thought of that.

Thanks
--
Tek
http://www.evilsuperbrain.com

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Sir Charles W. Shults III <aic### [at] cflrrcom> wrote in message
news:3e33130b$1@news.povray.org...
>     Definitely more grayness to them for realism.  Also, they should be much
> smoother.  And in space, if you were in an asteroid field, you would not see
> other asteroids nearby except as an occasional point of light moving very
slowly
> across the sky.
>     Let me dig out some of my asteroid stuff and see how they look.  Hopefully
I
> have something worth posting.
>     By the way, nice picture.

I'd be very interested to see a good realistic picture. I don't think I'll
bother making them realistic, but I'd still like to know how they should look.

BTW, why should they be smoother? Surely only the ones big enough to have some
significant gravity would be smooth ('cause they'll attract dust to get a smooth
surface). In case you're wondering these rocks are around 50m in diameter.

--
Tek
http://www.evilsuperbrain.com

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> The asteroids are created using 2 seperate effects:
> - The nearby asteroids are a mesh object created in Wings3d, with an agate
> normal map. There's only a hundred of these high detail ones, and probably
only
> about 30 of them can be seen in this shot.
> - The distant ones are part of the sky sphere, and are drawn using a
slightly
> complex texture based on the crackle pigment. They appear lit because
their
> colouring uses
> Anyway, the reason for my post is I want to know if this looks right to
you.
> Does it look like an asteroid field? Is it realistic or movie-style? (I'm
not
> sure how real ones compare to the ones I've seen in Star Wars!) Does nasa
have
> any photos? I couldn't find any good reference.

It looks great!
The ones far away are a bit smooth compared to the larger ones. But you
might not notice that in the movie because you are going to use a smaller
resolution, right?
Maybe some craters on the big ones would look cool? IIRC most of the
asteroids I've seen (mostly in movies) has a lot of them.
Another thing to get it realistic is how they move, especially the small
ones. Asteroids often spin, how do you plan to simulate this with a
procedular texture?

-Peter

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> Another thing to get it realistic is how they move, especially the small
> ones. Asteroids often spin, how do you plan to simulate this with a
> procedular texture?

Just commenting at that last sentence of yours:
Why not simply rotate the object AFTER the texture has been applied?
The texture will rotate with the object.
This isn't meant to be some scolding, but I am curios how you came
up with that idea?

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

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Tim Nikias <tim### [at] gmxde> wrote in message
news:3e33b434$1@news.povray.org...
> > Another thing to get it realistic is how they move, especially the small
> > ones. Asteroids often spin, how do you plan to simulate this with a
> > procedular texture?
>
> Just commenting at that last sentence of yours:
> Why not simply rotate the object AFTER the texture has been applied?
> The texture will rotate with the object.
> This isn't meant to be some scolding, but I am curios how you came
> up with that idea?

Well I animated them last night, and they're animated by rotating the objects.

However, I think Peter was probably referring to the more distant asteroids
which are just a procedural texture on the sky_sphere. In my test render these
are not spinning, but you don't notice it because of all the motion in the
foreground.

--
Tek
http://www.evilsuperbrain.com

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> > Just commenting at that last sentence of yours:
> > Why not simply rotate the object AFTER the texture has been applied?
> > The texture will rotate with the object.
> > This isn't meant to be some scolding, but I am curios how you came
> > up with that idea?
> However, I think Peter was probably referring to the more distant
asteroids
> which are just a procedural texture on the sky_sphere. In my test render
these
> are not spinning, but you don't notice it because of all the motion in the
> foreground.

I edited the post and forgot to read it again before posting. My fault :)
But I meant the asteroid texture on the sky_sphere, yes.

I'm looking forward to see more of the animation!

-Peter

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