Particle : Rate controled by distance ? 2005-05-21 - By Guillaume Laforge
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Thanks a lot Brad !!! Exactly what I need :-)
Cheers !
Guillaume
2005/5/21, Bradley R. Gabe <brad@(protected)>:
>
> I see what you are saying. What you want is for all your grids to be
> rotationally constrained to the camera.
> Orientation plus offset is not going to work, so use the following steps:
>
> 1- Turn on constraint compensation
> 2- Make sure the property page popup option is turned on
> 3- Select all your grids
> 4- Pose constrain all the grids to the camera
> 5- In the constraint multi select PPG, switch to the options tab and turn
> off scaling and position
> 6- Adjust your offset rotation values such that your grids face the camera
>
> If you need to rotate your grids in the camera plane, use the rotation
> axis in the constraint offset.
>
> -Brad
>
> 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>Thanks a lot Brad !!! Exactly what I need :-)</div>
<div> </div>
<div>Cheers !</div>
<div> </div>
<div>Guillaume<br><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">I see what you are saying. What you want is
for all your grids to be rotationally constrained to the camera.
<br>Orientation plus offset is not going to work, so use the following steps:
<br><br>1- Turn on constraint compensation<br>2- Make sure the property page
popup option is turned on<br>3- Select all your grids<br>4- Pose constrain all
the grids to the camera
<br>5- In the constraint multi select PPG, switch to the options tab and turn
off scaling and position<br>6- Adjust your offset rotation values such that
your grids face the camera<br><br>If you need to rotate your grids in the
camera plane, use the rotation axis in the constraint offset.
<br><br>-Brad
<div><span class="e" id="q_103fef94e7db52a1_1"><br><br>
<blockquote cite="http://" type="cite">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".
<br>Did I misunderstand something ?<br> <br>Guillaume<br> <br><br>
<br>2005/5/21, Bradley R. Gabe <<a onclick="return top.js.OpenExtLink
(window,event,this)" href="mailto:brad@(protected)" target="_blank">brad@(protected)
.com
</a>>: <br>
<dl>
<dd>Direction constraint towards camera with an up vector should do the trick.
<br>
<dd>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>
<dd>-Brad <br><br><br>
<blockquote cite="http://" type="cite">
<dd>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>
<dd>I can't find the way to constrain a grid to the camera like the particle
billboard facing the camera. <br>
<dd> <br>
<dd>Help !<br>
<dd> <br>
<dd>Cheers,<br>
<dd> <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><br><br>
<dd> <br>
<dd>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>>:
<dl>
<dd>Fantastic !
<dd>
<dd>Thanks for the tips :-) It works very well with the emitter animated along
a circle ( Particle clock look :-) )
<dd>Will be harder to use it in my scene (camera animation and interaction with
characters...) but I'll give it a try.
<dd>
<dd>Thanks again Eric.<br>
<dd>
<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>>:
<dl>
<dd>Emission is tied to frame rate, so you would get
<dd>better results if you changed it to an easily divided
<dd>number. For example, if you take small emitter say
<dd>the default sphere emitter scalled to .001, make the
<dd>emission rate 10, velocity 0, set the playback to 100
<dd>fps, key the emitter to move from -10 x to 10 x linear
<dd>keys. The resulting placement about 95% perfect,
<dd>there's a little variation but it's probably due to
<dd>scale. That will help as well, always make sure you
<dd>err on the side of a large scale as opposed to a small
<dd>one since when particles really get moving sometimes
<dd>you'll see big gaps in the emission.<br>
<dd>So in your case if you can scale your animation so
<dd>that it will match at 100fps you should be able to do
<dd>it more easily than, if you're stuck at 25, 30, 29.97
<dd>(which is the worst of this sort of thing) since you
<dd>to have your rate set to a factor of the FPS value.
<dd>10 of course is the easiest to work out.<br>
<dd>E<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>>
<dd>wrote:
<dd>> Hi,
<dd>> I've got an emitter animated along a curve. If I
<dd>> use the rate based on
<dd>> time, the distribution of particles along the curve
<dd>> isn't uniform because
<dd>> the Path %age isn't linear.
<dd>> I need a uniform space between each particles.
<dd>> Is it possible to emite one particle each n units
<dd>> of a curve ?
<dd>> Thanks,
<dd>> Guillaume Laforge
<dd>> CG artist
<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>>
<dd>><br>
<dd>Freelance 3-D Animator, F/X Artist, Particle Man
<dd>---
<dd>Unsubscribe? Mail <a onclick="return top.js.OpenExtLink(window,event,this)"
href="mailto:Majordomo@(protected)" target="_blank">Majordomo@(protected)<
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