[Sidefx-houdini-list] pcfilter point number

Olex P hoknamahn at gmail.com
Fri Aug 5 07:42:32 EDT 2011


Hi Nick,

It's not 1 node, it's several nodes (don't forget about AttribCreate
with $PT inside of it. Expressions are slow). I guess AttribTransfer
also creates some accelerator structures similar to what we have in
point clouds, so this stage can take the same amount of time. I'll do
a test to check what is faster and post results here.
About VEX vs C++. Usually VEX is faster as most of the C++ operators
are not multithreaded. One disadvantage of VEX is that it consumes
more RAM.


On Fri, Aug 5, 2011 at 12:07 PM, Nick Zutphen <nvanzutphen at live.com> wrote:
> Hi Oleg,
>
> I understand your reasoning, but what about setting the attribute transfer to 'max sample count' of 1 and keeping in mind that it is a native node which means its based on C++. I always figured that 'native' nodes are supposed to be faster than their equivalent in Vex, or am I unforgivably wrong?
>
> Cheers,
> Nick van Zutphen
> ----
> http://www.nickvanzutphen.com
>
> On Aug 5, 2011, at 12:15 PM, Olex P wrote:
>
>> Hi Nick,
>>
>> That point cloud solution is simplest ever and most efficient (as it
>> samples just 1 point). And a setup is just one VEX (or VOP if you
>> want) operator. I would upload a hip file but I don't know any
>> pastebin like service that supports bin files.
>>
>> On Fri, Aug 5, 2011 at 10:56 AM, Nick Zutphen <nvanzutphen at live.com> wrote:
>>> Hi Oleg,
>>>
>>> Thank you your your reply.
>>> I guess you're describing a similar approach to the one I mentioned in my first message.
>>>
>>> Initially I found it a rather complicated solution which I tend to avoid, especially in VOP's, that's why I tried to use pcfilter. It turned out that  'Attribute Transfer' works perfectly in this case.
>>>
>>> Cheers!
>>> Nick van Zutphen
>>>
>>> ----
>>> http://www.nickvanzutphen.com
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Aug 4, 2011, at 11:35 AM, Olex P wrote:
>>>
>>>> Hi guys,
>>>>
>>>> Hi guys, the first entry in a point cloud lookup is always a nearest
>>>> point. A following snipet of code will give you the number of nearest
>>>> point and a distance to it
>>>>
>>>> [code]
>>>> sop
>>>> pcnearest(string       pcfile  = "";
>>>>                float        radius = 1.0f;
>>>>
>>>>                export int   num = -1;
>>>>                export float dist  = -1.0f)
>>>> {
>>>>    int handle = pcopen(pcfile, "P", P, radius, 1);
>>>>
>>>>    if(pciterate(handle))
>>>>    {
>>>>        pcimport(handle, "point.number",   num);
>>>>        pcimport(handle, "point.distance", dist);
>>>>    }
>>>>
>>>>    pcclose(handle);
>>>> }
>>>> [/code]
>>>>
>>>> On Wed, Aug 3, 2011 at 9:14 PM, Alvaro Castaneda <varomix at gmail.com> wrote:
>>>>> 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
>>>>>  My profiles: [image: LinkedIn] <http://www.linkedin.com/in/varomix> [image:
>>>>> Twitter] <http://twitter.com/varomix> [image:
>>>>> Facebook]<http://www.facebook.com/varomix>
>>>>> 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
>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>  ______________________________****_________________
>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>  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>
>>>>>>>> <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>
>>>>>>>> <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>
>>>>>>>> <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>
>>>>>>>> <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
>>>>>>> ==============================**=========
>>>>>>> ______________________________**_________________
>>>>>>> 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
>>>>>
>>>> _______________________________________________
>>>> Sidefx-houdini-list mailing list
>>>> Sidefx-houdini-list at sidefx.com
>>>> 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
>>>
>> _______________________________________________
>> Sidefx-houdini-list mailing list
>> Sidefx-houdini-list at sidefx.com
>> 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
>



More information about the Sidefx-houdini-list mailing list