[Sidefx-houdini-list] Does $CH works in CHOPs?

Pablo Giménez Pizarro pablogipi at gmail.com
Wed Sep 7 19:54:08 EDT 2011


Yep I thought about the foreach. I think it will do the job, but is going to be slow as well. 
The expression I mentioned in my previous email is doing the job but for more complex situations foreach is probably the way to go. 
Thanks!

Enviado desde mi iPhone

El 7 Sep 2011, a las 19:02, mdunkley at gmail.com escribió:

> Hi Pablo -
> 
> Perhaps I'm misunderstanding the issue, but have you taken a look at the foreach chop? At its most basic, it will strip down your channels based on the channel indices you're talking about to let you work on everything that has the same index at once ( ie tx45 ty 45 tz 45 rx45 vx45, etc ), and give you channel ref access to the index number that you can use for randomness or anything else. So long as "organize by attribute" is set up in your geo chop, then those channel index numbers will correlate to the attribute you're organizing by.
> 
> hope that helps,
> mike
> 
> On , Pablo Giménez <pablogipi at gmail.com> wrote:
>> Thanks Francois.
> 
>> I have tried using the Expression Chop, but the problem is that $C returns
> 
>> the index of the channel.
> 
>> I am not interested in the channel index I am interested in the point index
> 
>> that this channel belongs to.
> 
>> For instance if you have lots of transforms channel, a transform for a point
> 
>> is: tx45 ty45 tz45
> 
>> the indexes for these channels could be anything, but the point is 45, I
> 
>> need to get this point index which is contained in the name.
> 
>> Or get a unique number for all t[xyz]45 channels, so I can apply the same
> 
>> randomness to all of them.
> 
>> If you know know you have 3 channels per point something like $C % ($NC / 3)
> 
>> could do the job.
> 
>> I think is just a workaround.
> 
>> What would be great will be to be able to apply an operation to a set of
> 
>> channels that belongs to the same point. Noise or Jiggle already do this I
> 
>> think. But would be nice to do it in all CHOPs.
> 
> 
> 
> 
> 
>> 2011/9/7 François Duchesneau sidefx at trinix.ca>
> 
> 
> 
>> > I think what you need is to use an Expression Chop and use the many
> 
>> > available expressions like ioc() etc and their variables like $C, $I.
> 
>> >
> 
>> > You can manipulate any data this way. Have a look at Vop Chop too.
> 
>> >
> 
>> > Hope this help.
> 
>> >
> 
>> > François
> 
>> >
> 
>> >
> 
>> > Pablo Giménez wrote:
> 
>> >
> 
>> >> Hi All.
> 
>> >> I a mtrying to get modify some chopd to get variations based on point id.
> 
>> >> For instance in a jiggle chop you use channels t[xyz]$PT.
> 
>> >> What I want to do is to extract the point id string and get a random
> 
>> >> number
> 
>> >> from it to modify the jiggle per point.
> 
>> >> In the help says $CH return the name of the current channel:
> 
>> >> http://www.sidefx.com/docs/**houdini11.0/expressions/_**globalshttp://www.sidefx.com/docs/houdini11.0/expressions/_globals>
> 
>> >> But trying something like:
> 
>> >> atof(strreplace($CH, "tx", ""))
> 
>> >> Doesnt work alway returns zero.
> 
>> >> Any idea how to do something like this?
> 
>> >> Thanks!
> 
>> >>
> 
>> >>
> 
>> >>
> 
>> > ______________________________**_________________
> 
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>> > https://lists.sidefx.com:443/**mailman/listinfo/sidefx-**houdini-listhttps://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list>
> 
>> >
> 
> 
> 
> 
> 
> 
> 
>> --
> 
>> Un saludo
> 
>> Best Regards
> 
>> Pablo Giménez
> 
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