[Sidefx-houdini-list] nonLinear fluid reTime (Nick Zutphen)

Nick Zutphen nvanzutphen at live.com
Fri Jul 8 15:32:42 EDT 2011


I haven't tested this yet but how about animating the 'scale time' on the dop network?

Cheers!
Nick van Zutphen

----
http://www.nickvanzutphen.com

On Jul 8, 2011, at 5:37 PM, sidefx-houdini-list-request at sidefx.com wrote:

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> Today's Topics:
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>   1. Re: nonLinear fluid reTime (Nick Zutphen)
>   2. Re: instance light + light mask (Larry Giunta)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Fri, 8 Jul 2011 12:54:52 +0200
> From: Nick Zutphen <nvanzutphen at live.com>
> Subject: Re: [Sidefx-houdini-list] nonLinear fluid reTime
> To: sidefx-houdini-list at sidefx.com
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> Content-Type: text/plain; charset="us-ascii"
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> On Jul 8, 2011, at 12:15 PM, sidefx-houdini-list-request at sidefx.com wrote:
> 
>> Send Sidefx-houdini-list mailing list submissions to
>> 	sidefx-houdini-list at sidefx.com
>> 
>> To subscribe or unsubscribe via the World Wide Web, visit
>> 	https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>> or, via email, send a message with subject or body 'help' to
>> 	sidefx-houdini-list-request at sidefx.com
>> 
>> You can reach the person managing the list at
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>> 
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of Sidefx-houdini-list digest..."
>> 
>> 
>> Today's Topics:
>> 
>>  1. Re: Fix copy stamp N and up rotations (Dan Wills)
>>  2. Re: Fix copy stamp N and up rotations (Pablo Gim?nez Pizarro)
>>  3. nonLinear fluid reTime (Ben Frost)
>>  4. Re: nonLinear fluid reTime (Szymon Kapeniak)
>>  5. Re: nonLinear fluid reTime (Olex P)
>>  6. Re: nonLinear fluid reTime (Szymon Kapeniak)
>>  7. Re: nonLinear fluid reTime (Olex P)
>> 
>> 
>> ----------------------------------------------------------------------
>> 
>> Message: 1
>> Date: Fri, 8 Jul 2011 09:20:57 +0930
>> From: Dan Wills <gdanzo at gmail.com>
>> Subject: Re: [Sidefx-houdini-list] Fix copy stamp N and up rotations
>> To: sidefx-houdini-list at sidefx.com
>> Message-ID:
>> 	<CAKnjVK3U-q-w_axx31xXS25BdGN+PDDUkW1omqaP6wns--485w at mail.gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1
>> 
>> Hey Pablo, there's also a great reference for exactly what attributes do to
>> copies/instances, here:
>> 
>> http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=6679
>> 
>> 2011/7/7 Pablo Gim?nez <pablogipi at gmail.com>
>> 
>>> Hi all.
>>> When using copy stamp, if you provide a N and up attributes the operator
>>> calculates the rotations using that coordiante system as a reference.
>>> I am having some troubles with some geometry that at some point just jumps,
>>> it orientation flickers. I have tought that probably the problem is that
>>> the
>>> copy operator is doing an euler rotation rather than using quaternions.
>>> Not sure if somebody else have had the same problem before, but any advice
>>> about waht is the best/easy way to get the same rotations but usign
>>> quaternions would be gret.
>>> Thanks!
>>> 
>>> --
>>> Un saludo
>>> Best Regards
>>> Pablo Gim?nez
>>> _______________________________________________
>>> Sidefx-houdini-list mailing list
>>> Sidefx-houdini-list at sidefx.com
>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>> 
>> 
>> 
>> ------------------------------
>> 
>> Message: 2
>> Date: Fri, 8 Jul 2011 09:36:55 +0200
>> From: Pablo Gim?nez Pizarro <pablogipi at gmail.com>
>> Subject: Re: [Sidefx-houdini-list] Fix copy stamp N and up rotations
>> To: "sidefx-houdini-list at sidefx.com" <sidefx-houdini-list at sidefx.com>
>> Message-ID: <E31565E8-B7A3-4EB3-AA5B-8D63FC53D37A at gmail.com>
>> Content-Type: text/plain;	charset=utf-8
>> 
>> Thanks a lot dan, great reference!
>> Best documentation a i have ever seen about copy sop and instancing. 
>> 
>> Enviado desde mi iPhone
>> 
>> El 8 Jul 2011, a las 01:50, Dan Wills <gdanzo at gmail.com> escribi?:
>> 
>>> Hey Pablo, there's also a great reference for exactly what attributes do to
>>> copies/instances, here:
>>> 
>>> http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=6679
>>> 
>>> 2011/7/7 Pablo Gim?nez <pablogipi at gmail.com>
>>> 
>>>> Hi all.
>>>> When using copy stamp, if you provide a N and up attributes the operator
>>>> calculates the rotations using that coordiante system as a reference.
>>>> I am having some troubles with some geometry that at some point just jumps,
>>>> it orientation flickers. I have tought that probably the problem is that
>>>> the
>>>> copy operator is doing an euler rotation rather than using quaternions.
>>>> Not sure if somebody else have had the same problem before, but any advice
>>>> about waht is the best/easy way to get the same rotations but usign
>>>> quaternions would be gret.
>>>> Thanks!
>>>> 
>>>> --
>>>> Un saludo
>>>> Best Regards
>>>> Pablo Gim?nez
>>>> _______________________________________________
>>>> 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
>> 
>> 
>> ------------------------------
>> 
>> Message: 3
>> Date: Fri, 8 Jul 2011 10:11:03 +0100
>> From: Ben Frost <benfrost3d at gmail.com>
>> Subject: [Sidefx-houdini-list] nonLinear fluid reTime
>> To: sidefx-houdini-list at sidefx.com
>> Message-ID:
>> 	<CA+jg9Yp2iUUbx39VwpPc-cKeZSFHSzm5uwosCH_kEyjEKKaJyA at mail.gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1
>> 
>> hi all..
>> 
>> I'm looking for anyones opinion regarding a non-linear reTime of a fluid
>> sim.. and possible approaches to take.. the reTime is quite severe.. going
>> from 24fps to around 432fps.. so 18 times slower.. and is based on a
>> particle sim..
>> 
>> at the moment I'm using a brute force method for having the subSteps at 18,
>> writing out the subFrame for each step.. and then read it back in, and
>> reTiming.. this works.. but as you can imagine the sim times goes through
>> the roof a bit.. and change the sim some what.. although it's more accurate
>> it does create the problem of previewing the simulation at 18 subSteps..
>> ideally I'd like to simulate at as fewer subSteps as possible.. until i'm
>> happy with the sim.. and then upRess and bake out subFrames/subSteps..
>> 
>> we've reTimed the particles using the velocities to interpolate and get us
>> the subFrames needed.. not sure there is a way to interpret this to fluid
>> though..
>> 
>> and to make things worse.. I've been shown an animatable "sim scale" option
>> in maya.. which works all too well.. I noticed houdini has the same option
>> of sim scale, but this is only able to be set at sim start.. just wondering
>> if this is possible to be manipulated and animate..?
>> 
>> anyway I'd be great to hear your opinions or possible more efficient less
>> brute force approach..
>> 
>> cheers
>> 
>> ben..
>> 
>> 
>> ------------------------------
>> 
>> Message: 4
>> Date: Fri, 8 Jul 2011 11:33:31 +0200
>> From: Szymon Kapeniak <szymon.kapeniak at gmail.com>
>> Subject: Re: [Sidefx-houdini-list] nonLinear fluid reTime
>> To: sidefx-houdini-list at sidefx.com
>> Message-ID:
>> 	<CAHDL27xt0Pt=rNEWfvEn3U_83qMtx9YbxtG_CcmxhhBD2PTwuQ at mail.gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1
>> 
>> Hey Ben,
>> fluids are volumes (SDF), so they could be interpolated by Timeblend,
>> Sequenceblend and Timeshift Sops, similarly to plain geometries. I've
>> never tried it on fluids, but theoretically this should work the same
>> as on smoke (unless interpolating SDF is more computational
>> problematic, than density fields).
>> 
>> So I would try to increase a little su- stepping to provide good
>> samples for extreme interpolation, and retime my SDFs (taken straight
>> from DOPS, without meshing), after which meshing should be possible as
>> usual.
>> 
>> 
>> hth,
>> skk.
>> 
>> 2011/7/8 Ben Frost <benfrost3d at gmail.com>:
>>> hi all..
>>> 
>>> I'm looking for anyones opinion regarding a non-linear reTime of a fluid
>>> sim.. and possible approaches to take.. the reTime is quite severe.. going
>>> from 24fps to around 432fps.. so 18 times slower.. and is based on a
>>> particle sim..
>>> 
>>> at the moment I'm using a brute force method for having the subSteps at 18,
>>> writing out the subFrame for each step.. and then read it back in, and
>>> reTiming.. this works.. but as you can imagine the sim times goes through
>>> the roof a bit.. and change the sim some what.. although it's more accurate
>>> it does create the problem of previewing the simulation at 18 subSteps..
>>> ideally I'd like to simulate at as fewer subSteps as possible.. until i'm
>>> happy with the sim.. and then upRess and bake out subFrames/subSteps..
>>> 
>>> we've reTimed the particles using the velocities to interpolate and get us
>>> the subFrames needed.. not sure there is a way to interpret this to fluid
>>> though..
>>> 
>>> and to make things worse.. I've been shown an animatable "sim scale" option
>>> in maya.. which works all too well.. I noticed houdini has the same option
>>> of sim scale, but this is only able to be set at sim start.. just wondering
>>> if this is possible to be manipulated and animate..?
>>> 
>>> anyway I'd be great to hear your opinions or possible more efficient less
>>> brute force approach..
>>> 
>>> cheers
>>> 
>>> ben..
>>> _______________________________________________
>>> Sidefx-houdini-list mailing list
>>> Sidefx-houdini-list at sidefx.com
>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>> 
>> 
>> 
>> 
>> -- 
>> skk.
>> 
>> 
>> ------------------------------
>> 
>> Message: 5
>> Date: Fri, 8 Jul 2011 10:55:43 +0100
>> From: Olex P <hoknamahn at gmail.com>
>> Subject: Re: [Sidefx-houdini-list] nonLinear fluid reTime
>> To: sidefx-houdini-list at sidefx.com
>> Message-ID:
>> 	<CAM=-8n64W+Sb7wEzPFLhttyBcBNkBG_-wPWS8--RoWQUcoKsKQ at mail.gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1
>> 
>> I don't think that blending of two volumes in substep makes any sense
>> especially if a difference in state of the fluid in two frames is high
>> enough. But we can jump from Eulerian coordinate system (grids with
>> static voxels and quantities going through this grid) to Lagrangian
>> (particles where every particle is a local coordinate system with some
>> quantity, let's say density, on it).
>> In other words we can advect particles using velocity field,
>> interpolate particle positions in subframes and put density and other
>> needed attributes back into a grid.
>> 
>> On Fri, Jul 8, 2011 at 10:33 AM, Szymon Kapeniak
>> <szymon.kapeniak at gmail.com> wrote:
>>> Hey Ben,
>>> fluids are volumes (SDF), so they could be interpolated by Timeblend,
>>> Sequenceblend and Timeshift Sops, similarly to plain geometries. I've
>>> never tried it on fluids, but theoretically this should work the same
>>> as on smoke (unless interpolating SDF is more computational
>>> problematic, than density fields).
>>> 
>>> So I would try to increase a little su- stepping to provide good
>>> samples for extreme interpolation, and retime my SDFs (taken straight
>>> from DOPS, without meshing), after which meshing should be possible as
>>> usual.
>>> 
>>> 
>>> hth,
>>> skk.
>>> 
>>> 2011/7/8 Ben Frost <benfrost3d at gmail.com>:
>>>> hi all..
>>>> 
>>>> I'm looking for anyones opinion regarding a non-linear reTime of a fluid
>>>> sim.. and possible approaches to take.. the reTime is quite severe.. going
>>>> from 24fps to around 432fps.. so 18 times slower.. and is based on a
>>>> particle sim..
>>>> 
>>>> at the moment I'm using a brute force method for having the subSteps at 18,
>>>> writing out the subFrame for each step.. and then read it back in, and
>>>> reTiming.. this works.. but as you can imagine the sim times goes through
>>>> the roof a bit.. and change the sim some what.. although it's more accurate
>>>> it does create the problem of previewing the simulation at 18 subSteps..
>>>> ideally I'd like to simulate at as fewer subSteps as possible.. until i'm
>>>> happy with the sim.. and then upRess and bake out subFrames/subSteps..
>>>> 
>>>> we've reTimed the particles using the velocities to interpolate and get us
>>>> the subFrames needed.. not sure there is a way to interpret this to fluid
>>>> though..
>>>> 
>>>> and to make things worse.. I've been shown an animatable "sim scale" option
>>>> in maya.. which works all too well.. I noticed houdini has the same option
>>>> of sim scale, but this is only able to be set at sim start.. just wondering
>>>> if this is possible to be manipulated and animate..?
>>>> 
>>>> anyway I'd be great to hear your opinions or possible more efficient less
>>>> brute force approach..
>>>> 
>>>> cheers
>>>> 
>>>> ben..
>>>> _______________________________________________
>>>> Sidefx-houdini-list mailing list
>>>> Sidefx-houdini-list at sidefx.com
>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>>> 
>>> 
>>> 
>>> 
>>> --
>>> skk.
>>> _______________________________________________
>>> Sidefx-houdini-list mailing list
>>> Sidefx-houdini-list at sidefx.com
>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>> 
>> 
>> 
>> ------------------------------
>> 
>> Message: 6
>> Date: Fri, 8 Jul 2011 12:06:15 +0200
>> From: Szymon Kapeniak <szymon.kapeniak at gmail.com>
>> Subject: Re: [Sidefx-houdini-list] nonLinear fluid reTime
>> To: sidefx-houdini-list at sidefx.com
>> Message-ID:
>> 	<CAHDL27w5aCtNRzOJujP8xZfcD=hKC8q1P=bHHknJb+gLrnCP4Q at mail.gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1
>> 
>> 2011/7/8 Olex P <hoknamahn at gmail.com>:
>>> I don't think that blending of two volumes in substep makes any sense
>>> especially if a difference in state of the fluid in two frames is high
>>> enough.
>> 
>> Well, people are using this technique to retime their smoke sims,
>> Olex. I understand why blending volumes works worse than particles,
>> but still it seems to be enough for most retiming cases, since frames
>> tend to be similar.
>> 
>> Agree though, particles from volume might work better for high displacements.
>> 
>> But we can jump from Eulerian coordinate system (grids with
>>> static voxels and quantities going through this grid) to Lagrangian
>>> (particles where every particle is a local coordinate system with some
>>> quantity, let's say density, on it).
>>> In other words we can advect particles using velocity field,
>>> interpolate particle positions in subframes and put density and other
>>> needed attributes back into a grid.
>>> 
>>> On Fri, Jul 8, 2011 at 10:33 AM, Szymon Kapeniak
>>> <szymon.kapeniak at gmail.com> wrote:
>>>> Hey Ben,
>>>> fluids are volumes (SDF), so they could be interpolated by Timeblend,
>>>> Sequenceblend and Timeshift Sops, similarly to plain geometries. I've
>>>> never tried it on fluids, but theoretically this should work the same
>>>> as on smoke (unless interpolating SDF is more computational
>>>> problematic, than density fields).
>>>> 
>>>> So I would try to increase a little su- stepping to provide good
>>>> samples for extreme interpolation, and retime my SDFs (taken straight
>>>> from DOPS, without meshing), after which meshing should be possible as
>>>> usual.
>>>> 
>>>> 
>>>> hth,
>>>> skk.
>>>> 
>>>> 2011/7/8 Ben Frost <benfrost3d at gmail.com>:
>>>>> hi all..
>>>>> 
>>>>> I'm looking for anyones opinion regarding a non-linear reTime of a fluid
>>>>> sim.. and possible approaches to take.. the reTime is quite severe.. going
>>>>> from 24fps to around 432fps.. so 18 times slower.. and is based on a
>>>>> particle sim..
>>>>> 
>>>>> at the moment I'm using a brute force method for having the subSteps at 18,
>>>>> writing out the subFrame for each step.. and then read it back in, and
>>>>> reTiming.. this works.. but as you can imagine the sim times goes through
>>>>> the roof a bit.. and change the sim some what.. although it's more accurate
>>>>> it does create the problem of previewing the simulation at 18 subSteps..
>>>>> ideally I'd like to simulate at as fewer subSteps as possible.. until i'm
>>>>> happy with the sim.. and then upRess and bake out subFrames/subSteps..
>>>>> 
>>>>> we've reTimed the particles using the velocities to interpolate and get us
>>>>> the subFrames needed.. not sure there is a way to interpret this to fluid
>>>>> though..
>>>>> 
>>>>> and to make things worse.. I've been shown an animatable "sim scale" option
>>>>> in maya.. which works all too well.. I noticed houdini has the same option
>>>>> of sim scale, but this is only able to be set at sim start.. just wondering
>>>>> if this is possible to be manipulated and animate..?
>>>>> 
>>>>> anyway I'd be great to hear your opinions or possible more efficient less
>>>>> brute force approach..
>>>>> 
>>>>> cheers
>>>>> 
>>>>> ben..
>>>>> _______________________________________________
>>>>> Sidefx-houdini-list mailing list
>>>>> Sidefx-houdini-list at sidefx.com
>>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>>>> 
>>>> 
>>>> 
>>>> 
>>>> --
>>>> skk.
>>>> _______________________________________________
>>>> 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
>>> 
>> 
>> 
>> 
>> -- 
>> skk.
>> 
>> 
>> ------------------------------
>> 
>> Message: 7
> 
> I haven't tested this yet but how about animating the 'scale time' on the dop network? Shouldn't that take care of all that you need including 'just sim what you need'?
> 
> Cheers,
> Nick van Zutphen
> 
> ----
> http://www.nickvanzutphen.com
>> Date: Fri, 8 Jul 2011 11:15:13 +0100
>> From: Olex P <hoknamahn at gmail.com>
>> Subject: Re: [Sidefx-houdini-list] nonLinear fluid reTime
>> To: sidefx-houdini-list at sidefx.com
>> Message-ID:
>> 	<CAM=-8n7D7L6kh3eczUQkKSr-VkC=3xO9tgzLXz1eJJrJCN8AuA at mail.gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1
>> 
>> I agree in some situations it works (clouds in the sky?). While in
>> others like let's say a plume of steam from a steam train (initial
>> velocity is about 50-75 m/s) it wouldn't work.
>> Plus particles have other benefits like additional details, rest positions etc.
>> 
>> On Fri, Jul 8, 2011 at 11:06 AM, Szymon Kapeniak
>> <szymon.kapeniak at gmail.com> wrote:
>>> 2011/7/8 Olex P <hoknamahn at gmail.com>:
>>>> I don't think that blending of two volumes in substep makes any sense
>>>> especially if a difference in state of the fluid in two frames is high
>>>> enough.
>>> 
>>> Well, people are using this technique to retime their smoke sims,
>>> Olex. I understand why blending volumes works worse than particles,
>>> but still it seems to be enough for most retiming cases, since frames
>>> tend to be similar.
>>> 
>>> Agree though, particles from volume might work better for high displacements.
>>> 
>>> ?But we can jump from Eulerian coordinate system (grids with
>>>> static voxels and quantities going through this grid) to Lagrangian
>>>> (particles where every particle is a local coordinate system with some
>>>> quantity, let's say density, on it).
>>>> In other words we can advect particles using velocity field,
>>>> interpolate particle positions in subframes and put density and other
>>>> needed attributes back into a grid.
>>>> 
>>>> On Fri, Jul 8, 2011 at 10:33 AM, Szymon Kapeniak
>>>> <szymon.kapeniak at gmail.com> wrote:
>>>>> Hey Ben,
>>>>> fluids are volumes (SDF), so they could be interpolated by Timeblend,
>>>>> Sequenceblend and Timeshift Sops, similarly to plain geometries. I've
>>>>> never tried it on fluids, but theoretically this should work the same
>>>>> as on smoke (unless interpolating SDF is more computational
>>>>> problematic, than density fields).
>>>>> 
>>>>> So I would try to increase a little su- stepping to provide good
>>>>> samples for extreme interpolation, and retime my SDFs (taken straight
>>>>> from DOPS, without meshing), after which meshing should be possible as
>>>>> usual.
>>>>> 
>>>>> 
>>>>> hth,
>>>>> skk.
>>>>> 
>>>>> 2011/7/8 Ben Frost <benfrost3d at gmail.com>:
>>>>>> hi all..
>>>>>> 
>>>>>> I'm looking for anyones opinion regarding a non-linear reTime of a fluid
>>>>>> sim.. and possible approaches to take.. the reTime is quite severe.. going
>>>>>> from 24fps to around 432fps.. so 18 times slower.. and is based on a
>>>>>> particle sim..
>>>>>> 
>>>>>> at the moment I'm using a brute force method for having the subSteps at 18,
>>>>>> writing out the subFrame for each step.. and then read it back in, and
>>>>>> reTiming.. this works.. but as you can imagine the sim times goes through
>>>>>> the roof a bit.. and change the sim some what.. although it's more accurate
>>>>>> it does create the problem of previewing the simulation at 18 subSteps..
>>>>>> ideally I'd like to simulate at as fewer subSteps as possible.. until i'm
>>>>>> happy with the sim.. and then upRess and bake out subFrames/subSteps..
>>>>>> 
>>>>>> we've reTimed the particles using the velocities to interpolate and get us
>>>>>> the subFrames needed.. not sure there is a way to interpret this to fluid
>>>>>> though..
>>>>>> 
>>>>>> and to make things worse.. I've been shown an animatable "sim scale" option
>>>>>> in maya.. which works all too well.. I noticed houdini has the same option
>>>>>> of sim scale, but this is only able to be set at sim start.. just wondering
>>>>>> if this is possible to be manipulated and animate..?
>>>>>> 
>>>>>> anyway I'd be great to hear your opinions or possible more efficient less
>>>>>> brute force approach..
>>>>>> 
>>>>>> cheers
>>>>>> 
>>>>>> ben..
>>>>>> _______________________________________________
>>>>>> Sidefx-houdini-list mailing list
>>>>>> Sidefx-houdini-list at sidefx.com
>>>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> --
>>>>> skk.
>>>>> _______________________________________________
>>>>> 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
>>>> 
>>> 
>>> 
>>> 
>>> --
>>> skk.
>>> _______________________________________________
>>> 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
>> 
>> 
>> End of Sidefx-houdini-list Digest, Vol 303, Issue 6
>> ***************************************************
>> 
> 
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Fri, 8 Jul 2011 11:37:35 -0400
> From: Larry Giunta <larry at gcreativestudios.com>
> Subject: Re: [Sidefx-houdini-list] instance light + light mask
> To: sidefx-houdini-list at sidefx.com
> Message-ID:
> 	<84EF6D79-8114-49C8-BD76-67B43A9058D8 at gcreativestudios.com>
> Content-Type: text/plain;	charset=UTF-8;	delsp=yes;	format=flowed
> 
> That was it Stephen. As also confirmed by the ever helpful people in  
> support categories is in fact the proper way to handle
> light masks for instanced lights. Got it working now.
> 
> Thanks so much for your advice ( and thanks to all for your responses )
> 
> Larry
> 
> 
> 
> 
> 
> On Jul 7, 2011, at 7:41 PM, Stephen Tucker wrote:
> 
>> 
>> You'll want to use categories when trying to do instanced light  
>> masking
>> 
>> 
>>> From: larry at gcreativestudios.com
>>> Date: Thu, 7 Jul 2011 19:04:07 -0400
>>> To: sidefx-houdini-list at sidefx.com
>>> Subject: Re: [Sidefx-houdini-list] instance light + light mask
>>> 
>>> Thanks for the feedback Skk,
>>> 
>>> I'll need to wrap my mind around that a bit. Gotta love the warning
>>> in the description on that node under help.
>>> 
>>> Man, I thought there would have been a more straight forward way to
>>> control light masks for instanced lights.
>>> 
>>> Larry
>>> 
>>> On Jul 7, 2011, at 6:30 PM, Szymon Kapeniak wrote:
>>> 
>>>> Hey Larry, the trick mentioned by Peter seems to work, but not in
>>>> light masks on objects. Try masks in illuminance loop instead.  If
>>>> I recall correctly this is because an instance name is treated in
>>>> Houdini as an error (since such light doesn't exist yet), and never
>>>> get passed to IFD file. Shaders parms are sent as such, so they can
>>>> work with light's names valid only for Mantra.
>>>> 
>>>> skk.
>>>> 
>>>> Dnia 7 lip 2011 o godz. 23:27 Larry Giunta
>>>> <larry at gcreativestudios.com> napisa?(a):
>>>> 
>>>>> Thanks Peter. I guess this is not as easy as I had hoped.
>>>>> 
>>>>> ok, I do find this syntax for the light name in the IFD.
>>>>> ray_property object name "/obj/light1:/obj/instance1:0"
>>>>> 
>>>>> However, I'm trying all kinds of variations of that name in the
>>>>> light mask and still no luck.
>>>>> Looks like it might be time to hit up support for thoughts on this
>>>>> unless the above info provides any clues to you.
>>>>> 
>>>>> Thanks again for your help and feedback.
>>>>> 
>>>>> Larry
>>>>> 
>>>>> On Jul 7, 2011, at 3:49 PM, Peter Bowmar wrote:
>>>>> 
>>>>>> Hi Larry,
>>>>>> 
>>>>>> As I recall, this is tricky but possible. The issue is that the
>>>>>> instanced lights get renamed by the instancer. I think you have to
>>>>>> look inside the IFD file to get the "actual" name of the instanced
>>>>>> light... If the light is "MyLight" in the Houdini file, it might
>>>>>> become "MyLight-1" or something but I forget exactly. Sorry I  
>>>>>> can't
>>>>>> help more...
>>>>>> 
>>>>>> Cheers,
>>>>>> 
>>>>>> Peter B
>>>>>> 
>>>>>> On 7 July 2011 09:55, Larry Giunta <larry at gcreativestudios.com>
>>>>>> wrote:
>>>>>>> hello all. I hope this is a simple question.
>>>>>>> 
>>>>>>> I'm instancing a light to an object with one point ( because the
>>>>>>> light needs
>>>>>>> to be placed inside/stay with a translucent object animated in
>>>>>>> DOPs)
>>>>>>> I also have other lights in the scene.
>>>>>>> 
>>>>>>> I want this one object to only be illuminated by the instanced
>>>>>>> light and not
>>>>>>> any other lights in the scene.
>>>>>>> However, I'm not sure how to enter this in the light mask.
>>>>>>> 
>>>>>>> It seems that if I enter anything other than * I don't get any
>>>>>>> illumination
>>>>>>> on that object.
>>>>>>> I've tried entering the instanced object and the source light
>>>>>>> explicitly.
>>>>>>> I've also tried entering * and then eliminating lights with  a ^
>>>>>>> string ....
>>>>>>> 
>>>>>>> but unless I enter a wide open * I don't seem to get any
>>>>>>> illumination on
>>>>>>> this surface.
>>>>>>> 
>>>>>>> Any thoughts??
>>>>>>> 
>>>>>>> 
>>>>>>> Thanks,
>>>>>>> 
>>>>>>> Larry
>>>>>>> 
>>>>>>> _______________________________________________
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>>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> -- 
>>>>>> Cheers,
>>>>>> 
>>>>>> Peter B
>>>>>> 
>>>>>> --No, I am not on Facebook.
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