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

Robert Kelly isstuff at gmail.com
Thu Mar 10 11:45:14 EST 2011


another way is to use material sop to do overrides per point. I use
this now to control the geometry that is delay loaded and other
material properties per point. There is a hit when generating the ifd
when the point count gets higher. If this isnt the best way i woud be
keen to use a better one.

On 10 March 2011 04:32, Ben Frost <benfrost3d at gmail.com> wrote:
> 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
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>> > >> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>> > >>
>> > >
>> > >
>> > >
>> > > --
>> > > =======================================
>> > > Andrew D Lyons | Digital Artist | http://www.tstex.com
>> > > =======================================
>> > > _______________________________________________
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