Re: "use backround shader"?

[David Shirk <dshirk(at)ilm.com>]

If it doesn't screw up something else in your scene, you could apply an 
override to the FG elements to disable secondary rays.

If you really want the groundplane to clip all FG objects, why not just 
use a camera projection of your background image with the shadow mixed 
on top? Unless you're really after that nicely distorted enviro sphere. 
 Works great for holdout objects and even shows up properly in OGL, 
which I've never been able to do with the maya bg shader! (not counting 
the shadow, of course)

-Dave


Tim Leydecker wrote:
> Hi David,
>
> thanks alot, that´s the look I´d like to get,
> unfortunately this only works if the FG
> elements don´t intersect the groundplane
> assigned the shadingnetwork you described.
>
> A similar approach (that also doesn´t work)
> is to plug the shadow node into a constant
> materials transparency, with an >invert inbetween.
>
> I´ve also fiddled with the various >soft3d>
> Env_cubic/Env_ball/Env_sphere material presets
> but couldn´t get those to line up with the pass>
> environment shaders?
>
> It´s also quite, ahem misleading, that "RGB"
> isn´t ticked by default in the shadow shader,
> would help quite a bit when testing things out...
>
> Cheers
>
> tim
>
> ----- Original Message ----- From: "David Shirk" <dshirk(at)ilm.com>
> To: <XSI(at)Softimage.COM>
> Sent: Monday, September 25, 2006 5:45 PM
> Subject: Re: "use backround shader"?
>
>
> > Hi Tim - this may not be as fast as maya's bg shader, but you can 
> > create the effect with a couple of nodes in the render tree:
> >
> > Plug a mixer2 into the ground plane's material surface input
> >
> > Plug a raytracing>refraction node into mixer base color (set 
> > refraction to 1, keep ior at 1)
> >
> > Set the mixer color 1 to black (0,0,0)
> >
> > Plug an illumination>shadow node into the mixer weight1 input
> >
> > Inspect the shadow node, check rgb "on"


--
| David Shirk | technical animator | industrial light + magic | x3555 |

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