[Sidefx-houdini-list] pcfilter point number
Nick Zutphen
nvanzutphen at live.com
Fri Aug 5 08:19:30 EDT 2011
Hi Oleg,
Dedication, I like it :-). I find your results very interesting, a point for vex.
I will keep this in mind, though for my current setup the attribute transfer and the attribute create node take 2.43 ms and 0.68 ms, in that respect I don't see the point of creating my own node.
Never the less thank you very much for your input.
Cheers,
Nick van Zutphen
----
http://www.nickvanzutphen.com
On Aug 5, 2011, at 2:06 PM, Olex P wrote:
> Okay,
> Simple grid, 5M points scattered, VEX 5.78 sec, C++ 8.18 sec. VEX is
> 1.42 times faster. Not a big deal especially if a number of points
> even smaller than that but still VEX is faster :)
>
> On Fri, Aug 5, 2011 at 12:42 PM, Olex P <hoknamahn at gmail.com> wrote:
>> 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
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
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>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
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>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> ______________________________****_________________
>>>>>>>>>>
>>>>>>>>>>>
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>>>>>>>>>>>
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>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> ______________________________****_________________
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>> Sidefx-houdini-list mailing list
>>>>>>>>>>
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>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> ______________________________****_________________
>>>>>>>>>> Sidefx-houdini-list mailing list
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>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> ==============================**=========
>>>>>>>>> Andrew D Lyons | Digital Artist | http://www.tstex.com
>>>>>>>>> ==============================**=========
>>>>>>>>> ______________________________**_________________
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