Or you could simply use a Color_Math shader set to "Add". Plug your image into "input1" and set "input2" to 0,0,0,1.
Alpha clipping to [0,1] will then take care of the rest.
Uses only 1 shader instead of 4. Shader connections aren't free ;-)
- ½
> -----Original Message-----
> From: owner-xsi(at)Softimage.COM
> [mailto:owner-xsi(at)Softimage.COM]On Behalf
> Of peter_b
> Sent: Monday, 31 October, 2005 15:54
> To: XSI(at)Softimage.COM
> Subject: Re: alpha issues with EXRs used in a constant shader
>
>
> came up here last week i think:
> split the file in r g and b with colorpickers, and recombine
> them again with
> rgba combine.
> in the rgba combine you have a slider for the alpha, that you
> put on 1.
>
>
>
>
> > Check your color clip settings. There's three of them:
> >
> > RGB: The alpha is clamped to be between 1.0 and the maximum
> of the R, G,
> and B values.
> > ALPHA: The RGB channels are clamped between 0.0 and the alpha value.
> > RAW: No clipping occurs but it forces pre-multiply on.
> >
> > You'll find them under "Active Effects" in the
> render/region options.
> >
> > - ½
> >
> > > -----Original Message-----
> > > From: owner-xsi(at)Softimage.COM
> > > [mailto:owner-xsi(at)Softimage.COM]On Behalf
> > > Of Benjamin Huber
> > > Sent: Monday, 31 October, 2005 15:30
> > > To: XSI(at)Softimage.COM
> > > Subject: alpha issues with EXRs used in a constant shader
> > >
> > >
> > > hi all,
> > >
> > > i'm using an EXR plugged into the colour channel of a
> > > constant shader. the EXR has no alpha. however, doing a
> > > render region and toggling between alpha and RGB shows that
> > > the RGB luminance is being used as alpha.
> > >
> > > i have no idea why, but i don't think it should be like that.
> > > other shaders don't behave like that.
> > >
> > > any ideas? i have a sample scene but it's kinda big (300k) -
> > > if anyone wants to fiddle around with it - let me know.
> > >
> > > thanks!
> > >
> > > -ben
> > >
> > > ---
> > > ben huber (x63291)
> > > bhuber(at)ilm.com
> > > ilm digimatte
> > > serious like ninjas
> > > ---
> > >
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