[Sidefx-houdini-list] delayed load points inheriting attributes..?

Ben Frost benfrost3d at gmail.com
Thu Mar 10 07:32:42 EST 2011


thats great guys.. thanks for your advice... I have a few things to go on
now..!
I'll see how I get on.. and time depending I'll attempt to avoid too much
hackery.. no promises though..! :P

cheers

ben..


On 10 March 2011 02:18, Sean Lewkiw <Sean.Lewkiw at cis-vancouver.com> wrote:

> Some notes on this...
>
> Jeff's notes:
> http://www.sidefx.com/index.php?option=com_content&task=view&id=1050&Itemid=216
>
> You can only apply shaders at the OBJ level if you want to use the
> instancepoint() expression. This makes it difficult to apply multiple
> textures and lighting models to an object. To get around this, assign
> attributes to the geo and use these to select textures/mattes/lighting
> models etc. in the shader.
>
> Velocity attribute motion blur built into a model will not be additive with
> object level blur. Therefore, if you want both deformation and
> transformation blur, you will need to not use velocity blur at the object
> level. This is problematic if you have a particle system with a changing
> point count, (most particle sims!) To work around this, re-order your points
> using CHOPs.
>
> Sean
>
>
>
>
>
> -----Original Message-----
> From: sidefx-houdini-list-bounces at sidefx.com [mailto:
> sidefx-houdini-list-bounces at sidefx.com] On Behalf Of Premamurti Paetsch
> Sent: Wednesday, March 09, 2011 5:15 PM
> To: sidefx-houdini-list at sidefx.com
> Subject: Re: [Sidefx-houdini-list] delayed load points inheriting
> attributes..?
>
> There's the instancepoint() expression that returns the point number you
> instanced onto at render time.
> So you might be able use something like: point("/obj/instance_on_me/",
> instancepoint(), "id" , 0 ) to return per-point attrs and and pass that on
> to your shader interface.
> Not sure how this would perform though...
>
> cheers,
> prema
>
> On 10 March 2011 06:32, Szymon Kapeniak <szymon.kapeniak at gmail.com> wrote:
>
> > Hmm, I would say that properties won't be passed to archive shaders...
> >
> > This is fairly simple as long as you have a single shader per baked
> > geometry, since you can apply it on instancing point, not instanced
> > archive (by using MaterialSOP with overrides).
> >
> > Once you want more then a single shader per instance, you need to bake
> > them into archive IFD, and from now on AFAIK you can't inherit point's
> > attributes to be passed  to DL shaders. Or I'm missing something
> > also...
> >
> > I don't think there is any elegant way for doing this other than
> > cleverly baking shaders for your archive with varying parameters
> > already in place.
> >
> > Some solution would be to open geometry of instancing points in an
> > archived shader and import your attributes by hand from there (far
> > from elegance I suppose).
> >
> > Another idea I used to think of was a custom VEX function returning
> > value from a database during render time. As it would be a vex
> > constant, performance should not be an issue I believe).
> >
> >
> > cheers!
> >
> > 2011/3/9 Andrew D Lyons <tstexture at gmail.com>:
> > > It's been a while since I looked at this (circa v9.0 alpha) but my
> > > understanding is that properties were the means to pass this stuff on
> > > nowadays.
> > >
> > > http://www.sidefx.com/docs/houdini9.5/shade/properties
> > >
> > > Cheers
> > >
> > > On 9 March 2011 10:04, Ben Frost <benfrost3d at gmail.com> wrote:
> > >
> > >> hello all..
> > >>
> > >> does anyone know how, with a Mantra Delayed Load and  instancing (ie
> > rand
> > >> animating geo loads per point)..  is it possible for the dynamically
> > loaded
> > >> geometry to inherit the points attributes inorder to be passed to
> a/the
> > >> shader..  ie, Cd, id, and other custom attributes for arbs..
> > >> only finding hacky ways at the moment..  and I'm figuring there is a
> > simple
> > >> way or something I'm missing...
> > >> if any one has come across this before and has any suggestions that's
> be
> > >> awesome..
> > >>
> > >> cheers
> > >>
> > >> ben...
> > >> _______________________________________________
> > >> Sidefx-houdini-list mailing list
> > >> Sidefx-houdini-list at sidefx.com
> > >> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> > >>
> > >
> > >
> > >
> > > --
> > > =======================================
> > > Andrew D Lyons | Digital Artist | http://www.tstex.com
> > > =======================================
> > > _______________________________________________
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