Particle : Rate controled by distance ? 2005-05-21 - By Guillaume Laforge
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Maybe I'm missing something but the Particle Billboard is always facing the
camera AND stay "vertical", the only change is it's screen size in relation
to the distance from the cam. It looks like a direction constraint but the
two other axis of rotation of the billboard always update to keep it
"vertical".
Did I misunderstand something ?
Guillaume
2005/5/21, Bradley R. Gabe <brad@(protected)>:
>
> Direction constraint towards camera with an up vector should do the trick.
> Don't forget, you can tell the constraint which axis you want to point
> towards the camera and which one points up with the up vector.
>
> -Brad
>
> After some tests I think I didn't need particles to do this. Some simple
> grids animated along the path should be easier to control...but I'm hitting
> an other wall :-(
> I can't find the way to constrain a grid to the camera like the particle
> billboard facing the camera.
>
> Help !
>
> Cheers,
>
> Guillaume Laforge
> CG artist
> www.vol2nuit.fr <http://www.vol2nuit.fr/>
>
>
> 2005/5/20, guillaume laforge <guillaume.laforge.3d@(protected)>:
> Fantastic !
>
> Thanks for the tips :-) It works very well with the emitter animated along
> a circle ( Particle clock look :-) )
> Will be harder to use it in my scene (camera animation and interaction
> with characters...) but I'll give it a try.
>
> Thanks again Eric.
>
>
> 2005/5/20, Eric Lampi <ericlampi@(protected)>:
> Emission is tied to frame rate, so you would get
> better results if you changed it to an easily divided
> number. For example, if you take small emitter say
> the default sphere emitter scalled to .001, make the
> emission rate 10, velocity 0, set the playback to 100
> fps, key the emitter to move from -10 x to 10 x linear
> keys. The resulting placement about 95% perfect,
> there's a little variation but it's probably due to
> scale. That will help as well, always make sure you
> err on the side of a large scale as opposed to a small
> one since when particles really get moving sometimes
> you'll see big gaps in the emission.
>
> So in your case if you can scale your animation so
> that it will match at 100fps you should be able to do
> it more easily than, if you're stuck at 25, 30, 29.97
> (which is the worst of this sort of thing) since you
> to have your rate set to a factor of the FPS value.
> 10 of course is the easiest to work out.
>
> E
>
> --- guillaume laforge < guillaume.laforge.3d@(protected)>
> wrote:
> > Hi,
> > I've got an emitter animated along a curve. If I
> > use the rate based on
> > time, the distribution of particles along the curve
> > isn't uniform because
> > the Path %age isn't linear.
> > I need a uniform space between each particles.
> > Is it possible to emite one particle each n units
> > of a curve ?
> > Thanks,
> > Guillaume Laforge
> > CG artist
> > www.vol2nuit.fr <http://www.vol2nuit.fr/> < <http://www.vol2nuit.fr/>
> http://www.vol2nuit.fr>
> >
>
> Freelance 3-D Animator, F/X Artist, Particle Man
> ---
> Unsubscribe? Mail Majordomo@(protected) with the following text in body:
> unsubscribe xsi
>
>
>
<div>Maybe I'm missing something but the Particle Billboard is always facing
the camera AND stay "vertical", the only change is it's screen size
in relation to the distance from the cam. It looks like a direction constraint
but the two other axis of rotation of the billboard always update to keep
it "vertical".
</div>
<div>Did I misunderstand something ?</div>
<div> </div>
<div>Guillaume</div>
<div> </div>
<div><br> </div>
<div><span class="gmail_quote">2005/5/21, Bradley R. Gabe <<a href="mailto
:brad@(protected)">brad@(protected)</a>>:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0
.8ex; BORDER-LEFT: #ccc 1px solid">Direction constraint towards camera with an
up vector should do the trick.<br>Don't forget, you can tell the constraint
which axis you want to point towards the camera and which one points up with
the up vector.
<br><br>-Brad
<div><span class="e" id="q_103fe733fc43cb7e_1"><br><br>
<blockquote cite="http://" type="cite">After some tests I think I didn't need
particles to do this. Some simple grids animated along the path should be
easier to control...but I'm hitting an other wall :-(<br>I can't find the way
to constrain a grid to the camera like the particle billboard facing the camera
.
<br> <br>Help !<br> <br>Cheers,<br> <br>Guillaume Laforge<br>CG
artist<br><a onclick="return top.js.OpenExtLink(window,event,this)" href="http:
//www.vol2nuit.fr/" target="_blank">www.vol2nuit.fr</a><br><br> <br>2005/5
/20, guillaume laforge <
<a onclick="return top.js.OpenExtLink(window,event,this)" href="mailto
:guillaume.laforge.3d@(protected)" target="_blank">guillaume.laforge.3d@(protected)<
/a>>: <br>
<dl>
<dd>Fantastic !<br>
<dd> <br>
<dd>Thanks for the tips :-) It works very well with the emitter animated along
a circle ( Particle clock look :-) )<br>
<dd>Will be harder to use it in my scene (camera animation and interaction with
characters...) but I'll give it a try.<br>
<dd> <br>
<dd>Thanks again Eric.<br><br>
<dd> <br>
<dd>2005/5/20, Eric Lampi <<a onclick="return top.js.OpenExtLink(window
,event,this)" href="mailto:ericlampi@(protected)" target="_blank">ericlampi@(protected)
.com</a>>: <br>
<dl>
<dd>Emission is tied to frame rate, so you would get<br>
<dd>better results if you changed it to an easily divided<br>
<dd>number. For example, if you take small emitter say<br>
<dd>the default sphere emitter scalled to .001, make the<br>
<dd>emission rate 10, velocity 0, set the playback to 100<br>
<dd>fps, key the emitter to move from -10 x to 10 x linear <br>
<dd>keys. The resulting placement about 95% perfect,<br>
<dd>there's a little variation but it's probably due to<br>
<dd>scale. That will help as well, always make sure you<br>
<dd>err on the side of a large scale as opposed to a small <br>
<dd>one since when particles really get moving sometimes<br>
<dd>you'll see big gaps in the emission.<br><br>
<dd>So in your case if you can scale your animation so<br>
<dd>that it will match at 100fps you should be able to do<br>
<dd>it more easily than, if you're stuck at 25, 30, 29.97<br>
<dd>(which is the worst of this sort of thing) since you<br>
<dd>to have your rate set to a factor of the FPS value.<br>
<dd>10 of course is the easiest to work out.<br><br>
<dd>E<br><br>
<dd>--- guillaume laforge <<a onclick="return top.js.OpenExtLink(window
,event,this)" href="mailto:guillaume.laforge.3d@(protected)" target="_blank">
guillaume.laforge.3d@(protected)</a>><br>
<dd>wrote:<br>
<dd>> Hi,<br>
<dd>> I've got an emitter animated along a curve. If I<br>
<dd>> use the rate based on<br>
<dd>> time, the distribution of particles along the curve<br>
<dd>> isn't uniform because <br>
<dd>> the Path %age isn't linear.<br>
<dd>> I need a uniform space between each particles.<br>
<dd>> Is it possible to emite one particle each n units<br>
<dd>> of a curve ?<br>
<dd>> Thanks,<br>
<dd>> Guillaume Laforge<br>
<dd>> CG artist<br>
<dd>> <a onclick="return top.js.OpenExtLink(window,event,this)" href="http:/
/www.vol2nuit.fr/" target="_blank">www.vol2nuit.fr</a> <<a onclick="return
top.js.OpenExtLink(window,event,this)" href="http://www.vol2nuit.fr/" target="
_blank">
</a><a onclick="return top.js.OpenExtLink(window,event,this)" href="http://www
.vol2nuit.fr/" target="_blank">http://www.vol2nuit.fr</a>><br>
<dd>><br><br>
<dd>Freelance 3-D Animator, F/X Artist, Particle Man<br>
<dd>---<br>
<dd>Unsubscribe? Mail <a onclick="return top.js.OpenExtLink(window,event,this)"
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</dl><br></dd></dd></dd></dd></dd></dd></dd></dd></dl></blockquote></span></div
></blockquote></div><br>
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