[Sidefx-houdini-list] local variables in VOP SOPs

Andrew D Lyons tstexture at gmail.com
Wed Dec 19 16:45:21 EST 2007


Yep - replace all parameter VOPs with and import_attribute VOP that
has aparameter VOP for the attrib name string. That seems to be the
best way to build generic modular OPs using VOPs - or ones that don't
have attrib names or vars baked into them anyway.

On a related note. I stand corrected on the hiding of ops. One of the
sidefx babes pointed out that the "ophide" commmand does that. You can
then stick ophide commands in the $HFS OPcustomize file. Could be
handy in combination with the HOUDINI_OTL_SCANPATH thingy.

User error strikes again...


On 18/12/2007, Jerry Corda-Stanley <jerry at intelligentcreatures.com> wrote:
> Well I trying to post process a particle system and thought a nice little
> VOP SOP could do that. I wanted to drive the attributes from a LUT,
> but i can't because it won't let me.
>
> It's just a pain because I now have to make an otl. And more so because the
> Globals VOP has all that already attached so you think it should work, and after
> bashing your head on the desk for a bit realise it don't.
>
> no worries, I'll just do a little attribute voodoo and trick it in to compliance.
>
>
>
> ----- "Ivan DeWolf" <ivan at martian-labs.com> wrote:
> > also, why would you want to? if you're asking Houdini to solve some
> > complex
> > expression in an argument field of a custom VEX SOP, doesn't it make
> > more sense
> > to do that computation in your VEX code? (or VOP net, whatever) you
> > have access
> > to the same point attributes, and you're already creating code (or
> > nets)...
> >
> > having said that, however, VEX (and VOPs) seems unable to read int
> > point
> > attributes, and 2-dimensional float point attributes. ID is an int
> > point
> > attrib, and life is a 2-d float point attrib.... so I usually precede
> > my VEX
> > SOP with a point SOP and set $CR to $LIFE and $CG to $ID and access Cd
> > in the
> > SOP, or something similar.... a minor hassle, but worth noting...
> > (unless this
> > has changed in H9.?.???)
> >
> >
> > Quoting Peter Bowmar <pbowmar at gmail.com>:
> >
> > > No Houdini locals work in VEX/VOP nodes. You have to put it into
> > the
> > > VOPnet itself as a Parameter VOP to get it to import. This is how
> > VEX
> > > works. It's for speed, as local variables are relatively slow to
> > > calculate whereas the pure VEX is very fast.
> > >
> > > Cheers,
> > >
> > > Peter B
> > >
> > > On 18/12/2007, Andrew D Lyons <tstexture at gmail.com> wrote:
> > > > Yeh - I hear you. Some Houdini locals work, and some don't from
> > > > memory. I'm surprised $LIFE doesn't.
> > > >
> > > > Good $localVar and expression support in Vex OP UI parameters
> > would be
> > > > the icing on the vex OP cake IMHO. Often it's necessary to wrap
> > vex
> > > > OPs in a HDA subnet that handles all the attribCreate nonsense
> > for
> > > > artists, but then you end up with 2 ops for every purpose in your
> > > > menus. One that does the raw vex number crunching and one that
> > has
> > > > high level bells and whistles for users. Often they are named in
> > a
> > > > similar way, and then people have to remember which OP is the
> > decoy
> > > > and which is the money (depending on how they look at it.)
> > > >
> > > > This brings me to another long-standing RFE - the ability to load
> > a
> > > > hda - and have it accessible - but yet not appear as clutter in
> > your
> > > > OPmenus. I thought that was going to be part of H9 - but I'm yet
> > to
> > > > see it. Anyone know what happened to that one?
> > > >
> > > > Cheers
> > > >
> > > >
> > > >
> > > > On 17/12/2007, Jerry Corda-Stanley
> > <jerry at intelligentcreatures.com> wrote:
> > > > > Well I created the VOP SOP in H9, and wanted to stick $LIFE in
> > the
> > > parameter
> > > > > field of the VOP I created to change the colour.
> > > > > I was trying to keep it neat with out messing about with
> > attribute
> > > creates
> > > > > and so on.
> > > > >
> > > > >
> > > > > ----- "Andrew D Lyons" <tstexture at gmail.com> wrote:
> > > > > > In the SOP parameters or in the VOPnet itself?
> > > > > >
> > > > > > Traditionally there have been problems with putting complex
> > > > > > expressions in the parms of a VEX OP. Often you have to
> > override VEX
> > > > > > parms by creating an attribute of the same name and type with
> > an
> > > > > > attribCreate SOP further up the chain. If you have a parameter
> > VOP of
> > > > > > the same name you generally pass things in that way.
> > > > > >
> > > > > > Cheers
> > > > > >
> > > > > > On 17/12/2007, Jerry Corda-Stanley
> > <jerry at intelligentcreatures.com>
> > > > > > wrote:
> > > > > > > How do I get local varaibles such as $ID and $LIFE to be
> > recognised
> > > > > > in a VOP SOP?
> > > > > > > I put together a SOP to futz around with stuff and it's
> > complaining
> > > > > > that the variables
> > > > > > > are undefined. So how do I define them?
> > > > > > > _______________________________________________
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> > > > > > >
> > > > > >
> > > > > >
> > > > > > --
> > > > > > =======================================
> > > > > > Andrew D Lyons | Digital Artist | http://www.tstex.com
> > > > > > =======================================
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> > > > >
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> > > > >
> > > >
> > > >
> > > > --
> > > > =======================================
> > > > Andrew D Lyons | Digital Artist | http://www.tstex.com
> > > > =======================================
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> > >
> >
> >
> > -Ivan
> >
> > ---------------------------------------------------------
> > "Perfection is achieved when nothing else can be removed"
> > -Yvon Chouinard
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-- 
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================



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