[Sidefx-houdini-list] HDK: parse point/prim groups

Szymon Kapeniak szymon.kapeniak at gmail.com
Wed Nov 30 06:39:57 EST 2011


2011/11/29 Andrew Lyons <tstexture at gmail.com>:
> <2c>
> I'm thinking it's acceptable to ask a user to put down a "group geometry"
> SOP and use the "Edit/Convert" functionality to prepare their data for your
> tool by converting the prim groups to point groups there. This would be
> consistent with Houdini in general.

Yes it would, although in my particular case, it's not a matter of
generality and coherence, but rather performance hit. Anyway, thanks
for your input. Looks like getting manually the list of point is a way
to go. I don't want to create/delete groups on the fly, again because
it's slow - at least prior H12.

thanks again,
skk.

> If you still want to do the convert for them, you might consider preserving
> the generalized nature of your deformer tool. You could do this by wrapping
> it in an otl with a group geometry SOP that does the convert. and perhaps a
> switch SOP so users can toggle the convert on and off. You could also
> expose a group mask at the top level for them to choose which groups to
> convert. The group conversion then becomes part of the new higher level
> tool - but it lives outside the deformer HDK code - which remains
> unencumbered by the demands of this particular use-case.
> </2c>
>
>
>
> On 28 November 2011 14:14, Szymon Kapeniak <szymon.kapeniak at gmail.com>wrote:
>
>> Thanks Andrew,
>>
>> 2011/11/28 Andrew Lyons <tstexture at gmail.com>:
>> > It is possible to have a point group called "group1" and a prim group
>> > called "group1" in the same geo detail. Note sure that you could avoiding
>> > testing for the existence of both at all times...
>> >
>> > Perhaps exposing a "group type" switch/menu parm on the node would help
>> > clarify user intent for the system?
>> >
>> > I might be missing something though.
>>
>> No, it was me blurring in fact simple question. You're right, groups
>> can be ambiguous, Let me rephrase my question: how to start with
>> primitive groups but utilitize at the end:
>> duplicatePointSource/cookInputPointGroups/FOR_ALL_OPT_GROUP_POINTS
>> combo (or any other performing similarly)?
>>
>> My Sop is a deformer working on points, but an user is providing
>> mostly prim groups, how to manage this without explicitly building
>> point group from prim vertices?
>>
>> thanks!
>>
>> > Cheers
>> >
>> >
>> > On 28 November 2011 13:27, Szymon Kapeniak <szymon.kapeniak at gmail.com
>> >wrote:
>> >
>> >> Hello,
>> >> I'd like to modify an user specified group whenever it is a point or
>> >> primitive group. The thing I'm doing in essence is that I iterate over
>> >> points belonging to a point group, *or* laying on a primitives
>> >> belonging to the prim group. Is there a dedicated way of doing this?
>> >>
>> >> Currently my sop uses SOP_Node::cookInputPointGroups() and iterates
>> >> with FOR_ALL_OPT_GROUP_POINTS macro and I would love to leave it this
>> >> way for, at least theoretical, optimization.
>> >>
>> >> Should I basically use things like, parseInputGroup(),
>> >> cookInputAllGroups(), and then manually figure out type of a group,
>> >> and in case of prim group, iterate over prim to add point to some
>> >> array, or... I have better option?
>> >>
>> >> thanks!
>> >> skk.
>> >> _______________________________________________
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>> >>
>> >
>> >
>> >
>> > --
>> > =======================================
>> > Andrew D Lyons | Digital Artist | http://www.tstex.com
>> > =======================================
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>>
>>
>>
>> --
>> skk.
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>
>
>
> --
> =======================================
> Andrew D Lyons | Digital Artist | http://www.tstex.com
> =======================================
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-- 
skk.



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