PDA

View Full Version : Particle help - offset saved motion



biliousfrog
08-30-2011, 11:51 AM
As the title suggests, I have a couple of pre-calculated particle objects which, for ease of creation, were produced at frame 0 in a clean scene and then imported (load from scene) into the master scene. The particle motion was calculated and saved as .pfx, now I need to change the start time for the particles...err...how?

There's an EditFX tab in the dynamic properties with an EditStart setting but that doesn't seem to do anything. What am I missing here?

ArtGoblin
08-30-2011, 11:59 AM
you need to keyframe the particle object to controll the start if I remember correctly

biliousfrog
08-30-2011, 12:13 PM
I've tried creating an extra set of keyframes on the frame I want it to start on and also moving the existing keyframe but that hasn't worked. I tried deleting the motion file, changing the start frame for the particles and loading the motion again but that didn't work either.

Using Lightwave is like trying to push treacle up a hill sometimes

DrStrik9
08-30-2011, 12:17 PM
Just thinking outside the box here. Maybe edit the pfx file with a text editor? (No, I've never tried it, but it might be worth a look.)

biliousfrog
08-30-2011, 12:21 PM
That's exactly what I'm attempting to do now but notepad is throwing a hissy fit so I'm not sure it will be possible

DrStrik9
08-30-2011, 12:25 PM
That's exactly what I'm attempting to do now but notepad is throwing a hissy fit so I'm not sure it will be possible

Yeah, that one's a crap shoot. Sometimes you can, and sometimes all you get is a screen full of icons and question marks. :)

You can get a programmer's editor (basically a text editor with more sophisticated capabilities - in case notepad is being cranky) out there on the net for free. Can't think of one offhand, so just say, "Google." :)

ArtGoblin
08-30-2011, 01:02 PM
ok... in the particle tab, under "file" you load up the pfx, then select playback mode key... and set a keyframe where you want it to start..... eeehhhhh I think ;)

biliousfrog
08-30-2011, 01:03 PM
I have tried that too...but I'll try again :D

biliousfrog
08-30-2011, 01:09 PM
Got it...when doing it by 'key' it changes the pivot location by the looks of it so, rather than having the particles where they should be, I needed to reset the particle location to 0,0,0.

Job done...thanks everyone :)

Chrusion
08-31-2011, 10:14 AM
when doing it by 'key' it changes the pivot location by the looks of it so, rather than having the particles where they should be, I needed to reset the particle location to 0,0,0.
Explain a bit better, please. Doing what by 'key'? Key means what? What 'pivot location' is changed... center of emitter? From where to where? Does 'reset particle location' mean physically moving the emitter to 0,0,0... before baking or after?

When I moved the emitter after 'baking' to PFX file it had no effect on where the particles originate. I could have used this technique in my currently rendering anim. Instead, I rebaked the particles to a new PFX file with a different start frame [380 v. 400 for the first one] so I could "double" up particle density rather than double particles emitted. Not sure why I did that.
.
.

biliousfrog
08-31-2011, 10:46 AM
What I did was saved the particle motion and then saved the scene - then loaded items from scene to get the particles into the scene I needed.

Just so we're on the same page

If you select the particle object and open the dynamic properties you'll see that most of the options are greyed out (because it's using baked motion) but there are some options in the EditFX tab, namely "Playback Mode".

If you select "Key" you can use a keyframe to trigger the particle motion.

The problem (or feature) I found is that when selecting "Key" the object's location and scale changed, making me think that the sim had disappeared. What had really happened is that the emitter's original position and scale needed resetting to the origin with a scale of 1,1,1.

It's a difficult thing to explain so I'd suggest creating a scene, creating an emitter at a random position, rotation and random scale, baking particles then loading into a new scene and choosing Playback Mode = Key...I'm not much of a technical guy but it's like the co-ordinate system changes from local to world or vice-versa.

Sensei
08-31-2011, 11:13 AM
I am using ConTEXT as programmer text editor.
http://www.contexteditor.org/

Chrusion
08-31-2011, 09:26 PM
It's a difficult thing to explain... but it's like the co-ordinate system changes from local to world or vice-versa.
No, that was very helpful. Thanks.
.

Greenlaw
03-24-2014, 06:24 PM
Wow, I'm surprised that I never needed to offset a PFX file before today. I needed to re-time a Flocking sim and I've been looking for a PFX player with an E button on it when I stumbled upon this thread and learned I was barking up the wrong tree. I know this is an old thread but I wanted to thank everybody above for the info--it's very helpful.

This does make me wonder why there is no PFX player with a proper Speed Envelope though. Or is there? I don't need it now but if anybody knows of one, please share the info. Thanks! :)

If there isn't, I hope in a future release, LW3DG can make a PFX player with controls that are consistent with the various MDD players. (Which could use a little updating for consistency themselves.)

G.

lertola2
06-24-2015, 05:33 PM
Thanks for this info. I never had to control the timing and placement of a particle simulation before. I spent the morning thinking I could not properly move the simulation around. biliousfrog's explanation above really helped me understand how to animate the overall simulation.

Chrusion
06-25-2015, 07:53 AM
The EASIEST way to retime and reposition a PFX is to install DPont's DP_Kit (if you haven't already). Then add Particle Scan to the emitter (Obj Prop. > Deform tab > Add Displacement), set its options to save as MDD (to default vertcache folder in content dir - make one if not there), do the scan, disable it AND the PFX plugin, add MDD_Emitter (Geometry tab > Add Custom Object ), load just-created MDD file, in its options enable Key Move and to retime, enable Remap and create envelope as desired (I believe you set time = 0 key to 0 and desired start key = 1 and to stepped, or speed up/slow down by using 0 to 1 ramps).

A side benefit to using an MDD-converted PFX is you get single-pass motion blur when attaching instances. Sadly, however, HVs still require multi-pass MB.

lertola2
06-25-2015, 03:13 PM
Thanks for the info Chrusion. I really appreciate it. Even after working with Lightwave for 17 years there is still a lot I don't know.

Chrusion
06-26-2015, 02:42 PM
You're welcome.

lertola2
06-26-2015, 03:35 PM
Chruson, I followed your directions and I am able to use the DP Motion Designer plugins to create an MDD of the file. However when using the MDD_Emitter I can not move the particles around. They seem to be locked to the place that they are recorded. Moving the object around has no effect on the particle position. Am I missing something or is that just the way it works?

Thanks,
-Joe

Chrusion
06-29-2015, 01:56 PM
Did you set Key-Move to On? I just loaded up a scene with MDD Emitter and can move the particle sim anywhere I want with this option On.

lertola2
06-30-2015, 10:09 AM
Did you set Key-Move to On? I just loaded up a scene with MDD Emitter and can move the particle sim anywhere I want with this option On.

That is it. Thanks.

bazsa73
01-24-2017, 12:11 PM
This thread saved my life. Thanks.

Boris Goreta
02-20-2019, 03:56 AM
Life saver too, thanks !

mummyman
02-20-2019, 06:59 AM
Yes, this is one of those things that you forget how to do because sometimes you don't always have to do it. After I bake out a .pfx file.. I go into a new empty scene.. add a new null then apply the baked motion and offset the keys. I've been stuck on forgetting to reset the null to 0,0,0 as well. So I keep a "working" scene in case I want to alter the pfx file. Then a new "baked" scene. I'm sure I'll have to refer back to this thread eventually too! Nice that it's helping us a few years later..