[Sidefx-houdini-list] About shaders

guillaume laforge guillaume.laforge.3d at gmail.com
Sun Sep 30 12:33:27 EDT 2007


>PS. About the translucency, I imagine I will have to jump to VOPS.

Yes.

Create a vop surface shader.
In this new vop add a Global Variable node. Negate N with a ... negate node.
Add a lighting model node. Choose Lambertian model. Plug the negate node in
the "nN" input.
It gives you a basic translucency shader.

Cheers

Guillaume.

On 9/30/07, Jordi Bares <jordibares at the-mill.com> wrote:
>
> I guess my next step as soon as I finish the project I am in is to go to
> our
> code and convert it.
>
> I feel SideFX should address those things that are so important for people
> moving away from other tools to start running in a production environment
> as
> fast as possible.
>
> Thanks,
> Jb
> PS. About the translucency, I imagine I will have to jump to VOPS.
>
>
> On 30/9/07 14:41, "guillaume laforge" <guillaume.laforge.3d at gmail.com>
> wrote:
>
> > Hi Jordi,
> >
> > I agree, a monolithic shader a la Mental Ray mia shader could be very
> handy.
> >
> >
> > Translucency effect looks like a good training with vops :-). I think
> you
> > need to use a negative normal vector for the dot product with the light
> > vector.
> >
> > In vop, you can use a Lambertian lighting model and plug a negative
> normal
> > vector in the nN input.
> > If you need some transparency, it can be useful to mix the translucency
> > factor with the transparency factor
> > like in the mia shader ( if translucency factor set to 1, transparency
> is
> > null ).
> >
> > Since I started to use Houdini, I think about building a monolithic vop
> > surface shader network too. If there is something like that on the web,
> I'm
> > interested too.
> >
> > Cheers
> >
> > Guillaume Laforge | La Maison
> >
> >
> >
> > On 9/30/07, Jordi Bares <jordibares at the-mill.com> wrote:
> >>
> >> I am using H8.1 for the project I am working, and specially on the
> shader
> >> area I feel a bit weird, specially because doesn't seem to have a
> >> monolithic
> >> general purpose shader that can cope with everydays' basic stuff.
> >>
> >> I am using VEX Layered surface I was expecting to have other tools also
> >> like
> >> simple translucency, incandescence...
> >>
> >> Is there anything I have missed? Would you recommend me to use another
> vex
> >> shader for the translucency? If so, which one, doesn't seem to be one.
> >>
> >> On another note, may be a community OTL that has wrapped this?
> >>
> >> Just as suggestion, here at The Mill we use all the time a monolithic
> and
> >> very optimized supershader that does all sorts of things, from blurry
> >> reflections, thin film, incandescence, transparency tricks, multiple
> mixed
> >> specular calculations (blinn, phong, etc..) plus we have setup a bunch
> of
> >> presets that do the job 95% of the cases with minor tweaks, probably
> one
> >> of
> >> the most productive tools we have.
> >>
> >> Any chance the Houdini community has developed something similar to
> share?
> >>
> >>
> >> In any case, I would like to ask specially about the translucency
> effect,
> >> anyone could point me in the right direction?
> >>
> >>
> >> Thanks in advance
> >> jb
> >>
> >>
> >> _______________________________________________
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> >> Sidefx-houdini-list at sidefx.com
> >> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >>
> >
> >
> >
> > --
> > Guillaume Laforge
> > _______________________________________________
> > Sidefx-houdini-list mailing list
> > Sidefx-houdini-list at sidefx.com
> > https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>
>
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-- 
Guillaume Laforge



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