[Sidefx-houdini-list] pcfilter point number

Andrew Lyons tstexture at gmail.com
Wed Aug 3 15:12:44 EDT 2011


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>>
>> [image:
>>
>
>  Twitter] http://twitter.com/varomix> [image:
>>
>
>  Facebook]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
>>
>
>  ______________________________**_________________
>>
>
>  Sidefx-houdini-list mailing list
>>
>
>  Sidefx-houdini-list at sidefx.com
>>
>
>  https://lists.sidefx.com:443/**mailman/listinfo/sidefx-**houdini-list<https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list>
>>
>
>
>
>
>  ______________________________**_________________
>>
>
>  Sidefx-houdini-list mailing list
>>
>
>  Sidefx-houdini-list at sidefx.com
>>
>
>  https://lists.sidefx.com:443/**mailman/listinfo/sidefx-**houdini-list<https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list>
>>
>
>
>
>
>  ______________________________**_________________
>>
>
>  Sidefx-houdini-list mailing list
>>
>
>  Sidefx-houdini-list at sidefx.com
>>
>
>  https://lists.sidefx.com:443/**mailman/listinfo/sidefx-**houdini-list<https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list>
>>
>
>
> ______________________________**_________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/**mailman/listinfo/sidefx-**houdini-list<https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list>
>



-- 
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================



More information about the Sidefx-houdini-list mailing list