 | | | setting initial state on particles (age lost?) | setting initial state on particles (age lost?) 2005-02-19 - By Vince Fortin
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Sorry I made a big copy/paste mistake... time to get some sleep I guess.
The scripted events should read like this:
' // pEvent that retrieves the age% values of the Cloud_InitState and
copy it to a pp User Parameter:
' // Every N=1 frame
' // VBScript
' // Per Cloud
set oCloudInit = Dictionary.GetObject("cloud_InitState")
if InSimFrame = 1 then
for i = 0 to oCloudInit.Particles.count -1
set oParticle = oCloudInit.Particles(i)
oParticle.attributes("InitAgeNormalized").value = oParticle.Age /
oParticle.AgeLimit
next
end if
' // end
' // pEvent that increments the size using both Cloud and
Cloud_InitState age values:
' // Every N=1 frame
' // VBScript
' // Per Particle
set oCloudInit = Dictionary.GetObject("cloud_InitState")
Age = inParticle.Age
AgeLimit = inParticle.AgeLimit
if inParticle.Id < oCloudInit.Particles.Count then InitAgeNormalized =
oCloudInit.Particles(inParticle.id).attributes("InitAgeNormalized").value
inParticle.Size = ((Age / AgeLimit)+ InitAgeNormalized) * 3
' // end
On Sat, 19 Feb 2005 19:05:42 -0500, Vince Fortin <vfortin@(protected)> wrote:
> Hello Sean (and Aloys)!
> As mentioned on this list a couple of days ago, you cannot modify the
> particle Age value. For some reasons it makes xsi crash!
>
> What happens when you set an Initial State to a particle Cloud is all
> Age values are zeroed and the remainder of each particle's life (in
> frames) becomes their new AgeLimit.
> Thus, as an example:
> particle ID 0 : 20 / 48 (42% of its life) becomes particle ID 0 : 0 /
> 18 (0% of its life)
> particle ID 1 : 11 / 55 (20% of its life) becomes particle ID 1 : 0 /
> 44 (0% of its life)
> particle ID 2 : 3 / 51 ( 6% of its life) becomes particle ID 2 : 0 /
> 48 (0% of its life)
>
> Not very convenient I agree!
> But there's a solution. Maybe it's not the best but it's working so far...
>
> Forget about fcurves. You cannot rely on them anymore for the reasons
> stated above. You'll need to control your size -or any other
> attribute- with scripting. If this is not possible in your shot then
> ignore the whole workaround! For this example, we will create a simple
> expression to increment the size according to the age%.
>
> 1) Ok, in your pType, create a float User Parameter named "InitAgeNormalized".
>
> 2) Then all you need is two simple pEvents:
>
> ' // pEvent that retrieves the age% values of the Cloud_InitState and
> copy it to a pp User Parameter:
> ' // Every N=1 frame
> ' // VBScript
> ' // Per Cloud
> set oCloudInit = Dictionary.GetObject("cloud_InitState")
> Age = inParticle.Age
> AgeLimit = inParticle.AgeLimit
> if inParticle.Id < oCloudInit.Particles.Count - 1 then
> InitAgeNormalized =
> oCloudInit.Particles(inParticle.id).attributes("InitAgeNormalized").value
> inParticle.Size = ((Age / AgeLimit)+ InitAgeNormalized) * 3
> ' // end
>
> ' // pEvent that increments the size using both Cloud and
> Cloud_InitState age values:
> ' // Every N=1 frame
> ' // VBScript
> ' // Per Particle
> set oCloudInit = Dictionary.GetObject("cloud_InitState")
> Age = inParticle.Age
> AgeLimit = inParticle.AgeLimit
> InitAgeNormalized = inParticle.attributes("InitAgeNormalized").value
> inParticle.Size = ((Age / AgeLimit)+ InitAgeNormalized) * 3
> ' // end
>
> As you can see it's pretty straight-forward. The new particles will
> see their age% added with their corresponding old particle's age%.
> That means they Init with the correct size value and it will continue
> to evolve in time.
> Some lines in there will cause errors until you actually SET an
> Initial State so feel free to quote them out or mute until you're
> ready to initial state your work!
>
> Any questions? Hope this makes sense, I find it more difficult to
> explain than set up ;)
>
> Vincent
>
> On Fri, 18 Feb 2005 13:54:27 -0600, Sean Dunn
> <sean@(protected)> wrote:
> > If I attempt to change the age of my particle through a particle event,
> > it crashes XSI. This happens in 4.0 and 4.2. Here are examples of what
> > I've been trying, and the result. My test case is just a grid emitter
> > that increases particle size with age, with a initial state set at frame
> > 40.
> >
> > Albeit, I just learned how to do particle events today.. Anything I'm
> > doing that's obviously wrong, that would obviously *crash* XSI?
> >
> > // This just causes an error, in the AgeArray assignment. As far as I
> > can
> > // tell with Jscript, AgeArray contains nothing, on either side of
> > // the assignment.
> > //Every N=1 frame event
> > //Per cloud trigger
> > //Code:
> > if(inSimFrame==1)
> > {
> > var init_cloud = Dictionary.GetObject("cloud_InitState");
> > inParticleCloud.Particles.AgeArray = init_cloud.Particles.AgeArray;
> > }
> >
> > // Crashes XSI
> > //Every N=1 frame event
> > //Per triggered particle
> > //Code:
> > if(inSimFrame==1)
> > {
> > inParticle.Age = 10;
> > }
> >
> > // Crashes XSI as well
> > //Every N=1 frame event
> > //Per cloud trigger
> > //Code:
> > if(inSimFrame==1)
> > {
> > var init_cloud = Dictionary.GetObject("cloud_InitState");
> > var dC;
> > for(dC=0; dC<inParticleCloud.Particles.Cloud; dC++)
> > {
> > if(dC<init_cloud.Particles.Count)
> > {
> > inParticleCloud.Particles.Item(dC).Age =
> > init_cloud.Particles.Item(dC).Age;
> > }
> > }
> > }
> >
> > -- --Original Message-- --
> > From: Aloys Baillet [mailto:aloys.baillet@(protected)]
> > Sent: Friday, February 18, 2005 10:55 AM
> > To: XSI@(protected)
> > Subject: Re: setting initial state on particles (age lost?)
> >
> > I think the error could come from the fact that the simulated cloud
> > and the InitState cloud had not the same number of particles...
> > And that's why you should have everything OK with the other solution...
> > I hope!
> >
> > On Fri, 18 Feb 2005 10:26:29 -0600, Sean Dunn
> > <sean@(protected)> wrote:
> > > My size is based on Age% via an fcurve. As long as I copy the ages
> > over
> > > through the particle event, it shouldn't need the sizes copied, since
> > > they're generated on the fly based on the age, right?
> > >
> > > The previous chunk of code you gave actually errored, saying that the
> > > argument was invalid on line 1. I was definitely set up for Jscript,
> > but
> > > I think I narrowed it down to that it didn't understand what the
> > > Particles member of Incloud1.Value was. I'll try the particle events
> > > solution now.
> > >
> > > Thanks for your help Aloys!
> > >
> > > Sean
> > >
> > > -- --Original Message-- --
> > > From: Aloys Baillet [mailto:aloys.baillet@(protected)]
> > > Sent: Thursday, February 17, 2005 3:30 PM
> > > To: XSI@(protected)
> > > Subject: Re: setting initial state on particles (age lost?)
> > >
> > > Sorry Sean, I think I might have misleaded you...
> > > The solution I gave you will only work if there is no change in the
> > > particle number and if the size of the particles is constant (this was
> > > the case for me last week).
> > > Else, you will have to set a particle event for the entire cloud on
> > > the first frame, and get the InitState cloud object (with GetObject)
> > > and copy the size and the age of the particles from one cloud to the
> > > other (copying particle rotations won't work).
> > > Don't hesitate to ask more if I am not clear!
> > >
> > > Aloys
> > >
> > > On Thu, 17 Feb 2005 17:46:52 +0100, Aloys Baillet
> > > <aloys.baillet@(protected)> wrote:
> > > > Hello Sean,
> > > > Initial States are a big pain... they don't keep Color, UVW, Ages,
> > > Sizes...
> > > > But You can do a little workaround for this:
> > > > Set a scripted operator on the Cloud, connect the initial state
> > cloud,
> > > > and put this JScript:
> > > >
> > > > Out.Value.Particles.ColorArray =
> > Incloud1.Value.Particles.ColorArray;
> > > > Out.Value.Particles.SizeArray = Incloud1.Value.Particles.SizeArray;
> > > > Out.Value.Particles.UVWArray = Incloud1.Value.Particles.UVWArray;
> > > > Out.Value.Particles.AgeArray = Incloud1.Value.Particles.AgeArray;
> > > >
> > > > Hope this helps...
> > > >
> > > > On Thu, 17 Feb 2005 10:34:09 -0600, Sean Dunn
> > > > <sean@(protected)> wrote:
> > > > >
> > > > >
> > > > >
> > > > > I've been trying to figure out a particle problem for a few hours
> > > now.. I
> > > > > can't find any references to it online. When I Set Initial State
> > on
> > > a very
> > > > > simple particle system with size based on age, it doesn't keep the
> > > initial
> > > > > sizes (or, it looks like, any other attribute based on age). It
> > > keeps the
> > > > > positions, but that is it. Anything based on age goes back to 0.
> > Is
> > > there
> > > > > any way to get around this? I've duplicated the behavior in 4.0
> > and
> > > 4.2. Is
> > > > > it possible to create a particle event that would store the age as
> > a
> > > custom
> > > > > attribute and then use that to drive the size? ..because that's
> > > what I'm
> > > > > going to try soon if I can't make it work correctly. And I want to
> > > avoid
> > > > > requiring a pre-roll animation, since the simulation is heavy.
> > > > >
> > > > >
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Sean
> > > > >
> > > > >
> > > >
> > > > --
> > > > Aloys Baillet - TD / R&D @ La Maison - www.alamaison.fr
> > > >
> > >
> > > --
> > > Aloys Baillet - TD / R&D @ La Maison - www.alamaison.fr
> > > ---
> > > Unsubscribe? Mail Majordomo@(protected) with the following text in
> > > body:
> > > unsubscribe xsi
> > >
> > > ---
> > > Unsubscribe? Mail Majordomo@(protected) with the following text in
> > body:
> > > unsubscribe xsi
> > >
> >
> > --
> > Aloys Baillet - TD / R&D @ La Maison - www.alamaison.fr
> > ---
> > Unsubscribe? Mail Majordomo@(protected) with the following text in
> > body:
> > unsubscribe xsi
> >
> > ---
> > Unsubscribe? Mail Majordomo@(protected) with the following text in body:
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> >
>
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