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lertola2
12-13-2016, 01:15 PM
I have an animation with a emitter spraying particles. At a certain point I would like to slow down and freeze the position of the particles then fly the camera through them. Is this possible? Any help would be greatly appreciated.

-Joe

Greenlaw
12-13-2016, 02:56 PM
Try DP's ParticleScan and convert the .pfx to .mdd.

First, I think you need to be using Partigons and not the 'Hypervoxel' mode. After that, bake the sim as PFX. Then, add ParticleScan and re-bake to an .mdd. Next, remove or disable ParticleFX and ParticleScan. Finally, add MD Reader and load the MDD.

You can re-time the MDD using the envelope in the Reader panel. Just add a curve that decelerates to 0% where you want it to 'freeze'.

Hope that works for you. It's actually been a while since I did this but I think the steps above should cover it.

pinkmouse
12-13-2016, 03:43 PM
I haven't done it for a while either, but that sounds about right.

daforum
12-13-2016, 03:55 PM
Thank you for the tips Greenlaw :thumbsup:
I've always been curious how to use ParticleScan.

So it only works with Partigons?
Is there any way to use it with Hypervoxels?

Greenlaw
12-13-2016, 04:20 PM
TBH, I'm not 100% certain about that. When I wrote that I was thinking you needed Partigons to make them visible to Layout but, on second thought, I'm not sure that really makes any sense for this technique. It really shouldn't matter for MDD.

Sorry, like I said, it's been a while. Please try it out when you can and let us know how it works for you. :)

Greenlaw
12-13-2016, 04:23 PM
BTW, you can use Hypervoxels with Partigons--you'll just need to hide the points from render. Partigons are just points that have been turned into single-point polygons.

As particles, Partigons can sometimes be easier to work with in Layout because they're always visible and they can be renderable when you want them to be.

MonroePoteet
12-13-2016, 06:12 PM
You might have some success using a Gradient on the Particle Age to increase the Resistance. Attached is a sample scene. The node setup uses DP Kit Particle Info node to translate the particle age into the particle resistance as the age goes from 0 to 60.

135322 135321

DP Kit is available here:

http://dpont.pagesperso-orange.fr/plugins/nodes/Additionnal_Nodes_2.html

Remember to support Denis financially if you can.

mTp

lertola2
12-13-2016, 07:44 PM
Try DP's ParticleScan and convert the .pfx to .mdd.

First, I think you need to be using Partigons and not the 'Hypervoxel' mode. After that, bake the sim as PFX. Then, add ParticleScan and re-bake to an .mdd. Next, remove or disable ParticleFX and ParticleScan. Finally, add MD Reader and load the MDD.

You can re-time the MDD using the envelope in the Reader panel. Just add a curve that decelerates to 0% where you want it to 'freeze'.

Hope that works for you. It's actually been a while since I did this but I think the steps above should cover it.

Thanks Greenlaw. This is working. I really appreciate your help.

lertola2
12-13-2016, 07:48 PM
You might have some success using a Gradient on the Particle Age to increase the Resistance. Attached is a sample scene. The node setup uses DP Kit Particle Info node to translate the particle age into the particle resistance as the age goes from 0 to 60.

135322 135321

DP Kit is available here:

http://dpont.pagesperso-orange.fr/plugins/nodes/Additionnal_Nodes_2.html

Remember to support Denis financially if you can.

mTp

Thanks MonroePoteet,
That is a nice setup but it is not exactly what I had in mind. Your particles don't all stop at the same time but its interesting that they all stop in the same region.

Prince Charming
12-13-2016, 07:56 PM
It doesn't have to be partigons, but you do need to check the "save lwo" option to save out a file with the points in it. You dont even need to calculate or save out the pfx before hand. It will still scan the particles and save the pfx file. This is useful because sometimes under certain circumstances calculating gives different results than non calculated... Before this plug there was no way to save out a non calculated pfx.

MonroePoteet
12-14-2016, 02:19 PM
Thanks MonroePoteet,
That is a nice setup but it is not exactly what I had in mind. Your particles don't all stop at the same time but its interesting that they all stop in the same region.

Ah, OK, I misunderstood. The setup I posted doesn't work the way I expected anyway, since the Resistance appears to be assigned when each particle is created not re-calculated (or set) per frame as I thought.

Attached is a sample scene which uses a Drag mode Wind object, stepping up the Power from 0% to 10000% at frame 60. With a Resistance of 0.1 on the particles, they stop dead at their position at frame 60. Of course, if you want them to slow down radically before stopping, you could use a TCB curve rather than Stepped.

mTp

MonroePoteet
12-14-2016, 08:38 PM
BTW, if you want the bullets to stop about the same place similar to the first (flawed) post I made, you can set the Drag Wind's Falloff Mode to Distance (rather than OFF as in the prior Drag Wind scene) and use a fixed radius on the Drag Wind (e.g. the default 1m). By moving the Wind object down the Z axis, the particles / bullets run into the Drag Wind and stop. In this scenario, the Power doesn't need an envelope to step it up. Sample scene attached.

mTp

lertola2
12-16-2016, 03:20 PM
BTW, if you want the bullets to stop about the same place similar to the first (flawed) post I made, you can set the Drag Wind's Falloff Mode to Distance (rather than OFF as in the prior Drag Wind scene) and use a fixed radius on the Drag Wind (e.g. the default 1m). By moving the Wind object down the Z axis, the particles / bullets run into the Drag Wind and stop. In this scenario, the Power doesn't need an envelope to step it up. Sample scene attached.

mTp

Thanks for these examples. You taught me something. Before I posted my question I spent a couple of hours trying to get the bullet time thing to work by playing with the settings on the emitter. I did not think to try a wind object. I tried to look up the wind settings in the manual but they are poorly documented. They don't mention the drag setting at all.

MonroePoteet
12-16-2016, 04:45 PM
Yes, the documentation doesn't really describe the various Wind types at all. I'm not sure but what trying to describe some of the types would be sort of redundant (e.g. the Vortex Wind type acts like a Vortex?), or include an explanation which delves into the implementation (math?) which might just confuses things. They're easy enough to set up, so they may be easier to understand by just trying them out.

Attached is a sample scene with a bunch of Emitters (with different Layout colors), wind FX objects with various Wind Types just to the right of an Emitter, and labels on the Emitters pointing to their Wind. All Emitters have an initial Motion of X=2.0 and a Resistance of 1.0 (required for wind to affect the particles). All Wind Types have a Radius of 1m and a Power of 100% (if applicable).

Very interesting watching the different effects each Wind has on the particles. I left the scene set at frame 300 to see the final result. I found it interesting to use the Center object mode (crosshair in the upper right corner of Layout), and then select each Wind object successively while the timeline is running.

Hope it helps, and helps me too!
mTp

P.S. I forgot to mention that because of the Resistance, once any particle leaves the influence of a Wind object, it drifts to a halt. If you want the influence of the Wind to be larger, you can change the Radius or the Falloff mode.


135336

lertola2
12-16-2016, 07:01 PM
Yes, the documentation doesn't really describe the various Wind types at all. I'm not sure but what trying to describe some of the types would be sort of redundant (e.g. the Vortex Wind type acts like a Vortex?), or include an explanation which delves into the implementation (math?) which might just confuses things. They're easy enough to set up, so they may be easier to understand by just trying them out.

Attached is a sample scene with a bunch of Emitters (with different Layout colors), wind FX objects with various Wind Types just to the right of an Emitter, and labels on the Emitters pointing to their Wind. All Emitters have an initial Motion of X=2.0 and a Resistance of 1.0 (required for wind to affect the particles). All Wind Types have a Radius of 1m and a Power of 100% (if applicable).

Very interesting watching the different effects each Wind has on the particles. I left the scene set at frame 300 to see the final result. I found it interesting to use the Center object mode (crosshair in the upper right corner of Layout), and then select each Wind object successively while the timeline is running.

Hope it helps, and helps me too!
mTp

P.S. I forgot to mention that because of the Resistance, once any particle leaves the influence of a Wind object, it drifts to a halt. If you want the influence of the Wind to be larger, you can change the Radius or the Falloff mode.


135336

Wow. Thanks for preparing that file. It is very informative and I am going to stash it with my collection useful scenes. I can tell what most of the modes do by watching them except for the sticky wind. I noticed that you did not include the drag mode. My guess is that the drag mode is a kind of anti-wind that just stops particles in their tracks.

MonroePoteet
12-17-2016, 09:51 AM
Yes, these type of "test scenes" are really helpful. As you remember, after you demonstrated the incredible versatility of the Bend deformation tool (spiral spring, flat-to-sphere world and paper clip), I set up a deformers test scene with all the various deformers labeled and colored. The labeling (using the Custom Object Object Type plugin) and coloring really helps identify the "players" so I can test without constantly going back and trying to remember what I'd set up.

Here's a modified scene adding the Drag Wind. It looks to me like the Sticky Wind is similar to the Drag Wind except the particles have different drag applied to them depending on their distance from the center of the Wind object, while Drag Wind looks consistent so all the particle decelerate into a common plane. Maybe?

mTp

pming
12-24-2016, 07:44 AM
Hiya!

This is a bit old of a reply, and probably won't work (I don't/haven't animated in LW yet...just model). But have you thought about just doing it the way they actually do it "in real life"? To get "bullet time" they have a separate camera for each frame, and fire off each in succession. Costs lots of money and takes lots of time...but with 3D, we have access to infinite numbers of cameras. Run the sim, recording from one camera, then just switch to a one-camera-per-frame when you want to do your bullet time.

I don't know...maybe it's more work than I think it should be (copy/pasting each camera for each frame?). *shrug* Just a thought.

jeric_synergy
12-24-2016, 11:56 AM
I tried to look up the wind settings in the manual but they are poorly documented. They don't mention the drag setting at all.

::cough:: :devil:

OK, again: if USERS could amend the documentation, someone in the past five years WOULD HAVE already filled in this particular gap in the dox.

cove
12-25-2016, 03:26 PM
I have an animation with a emitter spraying particles. At a certain point I would like to slow down and freeze the position of the particles then fly the camera through them. Is this possible? Any help would be greatly appreciated.

-Joe

The Flocking feature may be usefull here.
Tried a few tests.
Refer to attatched images for setting you may want to try out.

Image 1. Particles arrive/stop at a flat surface.

Image 2. Particles arrive/stop on a multi distributed object created in modeler.

Hope this helps and your sober enough to give it a go after the festive weekend :beerchug:.