Re: Starfield Environment Shader

[Stephen Parish <sparish(at)ilm.com>]

A while back I had to make a nice starfield to fly through, I tried the 
particle method and it was fine but such a hassle when wanting to render 
with motion blur (this was back in 3.5).. So in the end I used lots of 
simple squares, I made zillions of them and then used the randomize 
function in the transform panel to put them all over the place. I used a 
constant white material on them and in comp I added a glow.. they 
rendered easily and super fast and you have good control over where they go.



Steve


Adrian Lopez wrote:

> Nice suggestion, Joe - I gave it a shot - and it sort of works.   
> There's a lack of control, however, that I find unsettling.  I cant 
> model concentrations of stars, or control the spread in other areas of 
> the sky.  I suppose you could use textures or weight maps to control 
> the emission - but God, its such a struggle.
>
> On 1/10/07, *Joe Laffey* <joe(at)laffey.tv <mailto:joe(at)laffey.tv>> wrote:
>
>     On Wed, 10 Jan 2007, Wayne Williams wrote:
>
>     > I didn't know single point polys existed. Don't you have to have at
>     > least 3 for it to be considered a polygon? Otherwise it's a point or
>     > line ya?
>
>
>     Technically yes, given the etomology of the word (many angles).
>
>     I would guess the OP has come from LightWave where there is
>     support for
>     render single point polygons (which are a distinct entity from
>     points) as
>     pixels. They work quite well for stars.
>
>     As far as making stars in XSI what about making a very large
>     sphere set to
>     emit particles with speed 0 in its volume.
>
>     Like this:
>
>
>     CreatePrim "Sphere", "MeshSurface"
>     CreateParticleCloud "sphere"
>     SetValue "cloud.cloud.ParticlesOp.sphere_emission.Generation", 3
>     SetValue "cloud.cloud.ParticlesOp.sphere_emission.Speed", 0
>     SetValue "cloud.cloud.ParticlesOp.sphere_emission.Rate ", 20000
>     NextFrame
>
>     Then set an initial state, or have the rate drop to 0, or
>     export/import
>     etc.
>
>     Then you use one of the particle shaders to get stars, you can
>     even give
>     them random colors, and random scales, which tend to look very
>     good for
>     stars.
>
>     --
>     Joe Laffey                |       Visual Effects for Film and Video
>     LAFFEY Computer Imaging   |     -------------------------------------
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> --
> Adrian Lopez
> CEO | Director | Producer
> Liquid Light Digital
> Kingston, Jamaica
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>
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> HD/SD Production | VFX & Animation | Production Management 



--
 steve parish | digimatte artist | industrial light + magic | x2652


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