[Sidefx-houdini-list] pcfilter point number

Alvaro Castaneda varomix at gmail.com
Wed Aug 3 16:14:44 EDT 2011


I think you're trying to do something more complex than it need to be
we get sometimes caught in that, but always the best thing is a simple
solution
simple to develop and simple to use.

Cheers





  *.:varomix:.*
MIX Studio
3D Artist/Generalist TD
www.varomix.net
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On Wed, Aug 3, 2011 at 2:00 PM, Nick van Zutphen <nvanzutphen at live.com>wrote:

> @ Andrew
> Ghehe, well with all due respect but your solution, compared to what I was
> doing, is almost ridiculous due to its simplicity. But I like it! :-). It
> works perfectly. Thanks a lot.
>
> @Mike
> I have to keep this in mind because I'm pretty sure I'll run in to this one
> again. Pcfilter works perfect if you would like to get position of 1 or
> especially an average of multiple points, to bad it doesn't do the trick in
> this case. Thank you for your input, it's much appreciated. Though Andrews
> solution is, in this particular case, the way to go.
>
> Case closed, (with that paper file and red 'case closed' stamp on it ;-)
> Nick van Zutphen
> ------------------------------**--------------------
> From: "Andrew Lyons" <tstexture at gmail.com>
> Sent: Wednesday, August 03, 2011 9:12 PM
>
> To: <sidefx-houdini-list at sidefx.**com <sidefx-houdini-list at sidefx.com>>
> Subject: Re: [Sidefx-houdini-list] pcfilter point number
>
>  Not totally clear on the problem - but I've always used the attribTransfer
>> SOP to get near points:
>>
>> 1./ Create custom point "ptnum" int attr. Store $PT in there.
>> 2./ attrTransfer ptnum to new geometry. (Set "Max Sample Count" set to 2
>> if
>> feeding same SOP into both inputs. Set to 1 otherwise.)
>>
>> Cheers
>>
>> On 3 August 2011 11:32, <mdunkley at gmail.com> wrote:
>>
>>  Hey Nick -
>>>
>>> I've had some fiddly problems using pcfilter for point numbers in the
>>> past.
>>> I was attempting to create a float point number variable called ptnum and
>>> just look it up with no interpolation (ie 1 point lookup) from pcfilter,
>>> but
>>> even then i would often get incorrect values - I think the filter is
>>> doing
>>> some kind of filtering no matter what. Sometimes the ptnum value it
>>> returned
>>> would just be a number off, as if it was getting ceil'ed or floor'ed,
>>> some
>>> times it came back with a floating point component, so clearly there was
>>> some sort of interpolation happening.
>>>
>>> I can say for sure that the other method you mentioned *does* work.
>>> Pciterate doesn't really do anything on its own - you need it to feed a
>>> while loop (both ouside the loop, and then again on the inside). Within
>>> the
>>> while, you can then use pcimport with "point.number" / "point.distance"
>>> to
>>> pull all that info out. My impression of pcfilter is that its just a
>>> quick
>>> and dirty one-stop-shop way to slew values between points, not to
>>> intended
>>> to work with the other point cloud functions - if you need to do anything
>>> very specific you'll have to roll your own with pciterate and a while
>>> loop.
>>>
>>> If you haven't seen it, check out peter quint's point cloud videos on
>>> vimeo
>>> - the second one talks very specifically about some of the issues related
>>> to
>>> making your own:
>>> http://vimeo.com/9108284
>>>
>>> Best,
>>> Mike
>>>
>>>
>>>
>>> On , Nick van Zutphen <nvanzutphen at live.com> wrote:
>>>
>>>  I like to stay close to 'SESI' guidelines, or like the default tools
>>>> work
>>>> (something I inherited from my intenship). I guess giving a position
>>>> vector,
>>>> which can also be set by using a handle is pretty close to that.
>>>> Obviously
>>>> using a sphere would work, but it's not very neat, is it?
>>>>
>>>>
>>>
>>>
>>>  Cheers,
>>>
>>>>
>>>>
>>>  Nick van Zutphen
>>>
>>>>
>>>>
>>>
>>>
>>>  ------------------------------****--------------------
>>>
>>>>
>>>>
>>>  From: "Alvaro Castaneda" varomix at gmail.com>
>>>
>>>>
>>>>
>>>  Sent: Wednesday, August 03, 2011 6:21 PM
>>>
>>>>
>>>>
>>>  To: sidefx-houdini-list at sidefx.com****>
>>>
>>>>
>>>>
>>>  Subject: Re: [Sidefx-houdini-list] pcfilter point number
>>>
>>>>
>>>>
>>>
>>>
>>>
>>>  This might be a dumb idea, but why don't you
>>>
>>>>
>>>>
>>>  ask the user to place a sphere for initial position
>>>
>>>>
>>>>
>>>  use that to grab any points inside and start from there?
>>>
>>>>
>>>>
>>>
>>>
>>>  I can use that :)
>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>  
>>>
>>>>
>>>>
>>>
>>>
>>>  *.:varomix:.*
>>>
>>>>
>>>>
>>>  MIX Studio
>>>
>>>>
>>>>
>>>  3D Artist/Generalist TD
>>>
>>>>
>>>>
>>>  www.varomix.net
>>>
>>>>
>>>>
>>>  My profiles: [image: LinkedIn] http://www.linkedin.com/in/****varomix<http://www.linkedin.com/in/**varomix>
>>> <http://www.linkedin.**com/in/varomix<http://www.linkedin.com/in/varomix>
>>> >>
>>>
>>>> [image:
>>>>
>>>>
>>>  Twitter] http://twitter.com/varomix> [image:
>>>
>>>>
>>>>
>>>
>>> Facebook]http://www.facebook.****com/varomix<http://www.**
>>> facebook.com/varomix <http://www.facebook.com/varomix>>
>>>
>>>> >
>>>>
>>>>
>>>  On Wed, Aug 3, 2011 at 10:06 AM, Nick van Zutphen nvanzutphen at live.com
>>>
>>>> >wrote:
>>>>
>>>>
>>>
>>>
>>>
>>>  Hi!
>>>
>>>>
>>>>
>>>
>>>
>>>  I finally figured out how this maillist thing works :-), at least I hope
>>>
>>>>
>>>>
>>>  so. It feels a bit like 'you're used to Internet, and you have to use
>>> 'the
>>>
>>>>
>>>>
>>>  wire', telex or how ever it's called in English' ;-).
>>>
>>>>
>>>>
>>>
>>>
>>>  I'm working on a tool which operates on scattered points and it needs a
>>>
>>>>
>>>>
>>>  starting point. I would like to give the user the ability to specify a
>>>
>>>>
>>>>
>>>  position vector and the tool will figure out what the closest point is.
>>>
>>>> This
>>>>
>>>>
>>>  becomes need when you would like to start in a certain area and the
>>> points
>>>
>>>>
>>>>
>>>  might change due to a different seed or what so ever.
>>>
>>>>
>>>>
>>>
>>>
>>>  I think of a pointcloud method, however I'm interested in the closest
>>>
>>>> point
>>>>
>>>>
>>>  pointnumber. I know pciterate has the option point.number but that
>>> doesn't
>>>
>>>>
>>>>
>>>  seem to work on pcfilter and ptnum doesn't give any luck either. I would
>>>
>>>>
>>>>
>>>  like to use pcfilter since it's about a single point and iterating over
>>> 1
>>>
>>>>
>>>>
>>>  point doesn't seem to make much sense.
>>>
>>>>
>>>>
>>>
>>>
>>>  So my question is: 'Is there a way to get the point number when using
>>>
>>>>
>>>>
>>>  pcfilter. If not, what's the alternative?'
>>>
>>>>
>>>>
>>>
>>>
>>>  Cheers!
>>>
>>>>
>>>>
>>>  Nick van Zutphen
>>>
>>>>
>>>>
>>>  ______________________________****_________________
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>>
>>
>> --
>> ==============================**=========
>> Andrew D Lyons | Digital Artist | http://www.tstex.com
>> ==============================**=========
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