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View Full Version : Lack of WeightMap option for Birth rate in Emitter



Farhad_azer
10-22-2015, 08:28 AM
why is it so?

I thought I can multiply procedural textures by gradient layer that has weightmap as input in order to force some part of objects to emit particle BUT there is no weightmap option there.

Then I found node editor under the list of procedurals and sadly we can not assign weightmap node there too.

I am asking this out of curiosity and it is not super important for now.

How do you guys make only some polies to shoot particles rather than whole objects (beside detaching poly in modeler option).

prometheus
10-22-2015, 03:25 PM
why is it so?



I thought I can multiply procedural textures by gradient layer that has weightmap as input in order to force some part of objects to emit particle BUT there is no weightmap option there.

Then I found node editor under the list of procedurals and sadly we can not assign weightmap node there too.

I am asking this out of curiosity and it is not super important for now.

How do you guys make only some polies to shoot particles rather than whole objects (beside detaching poly in modeler option).

unfortunatly no weight map option, why? they havenīt gotten around to make it work...a plugin developer did a plugin that could deal with it..see below.
you have to use those polys you want to emitt in itīs own layer and use that as emitting object.
There is no way to emitt particles based on weightmaps sadly, I have requested that for particle enhancements as well as a weight paint tool in layout to make the workflow of painting in scene context much easier..we have to wait and see.
there is a particle plugin commercial..called fire and smoke generator from pavel olas, it can use weightmaps for particle emission but is specially designed for fire and smoke.

you can use image map or procedurals only to emitt particles in the birth channel, preferably you set a luminosity channel up or color channel so you see the procedural in opengl or vpr and then copy it to the particle emitters birth rate.

for polys to shoot particles..simply create a poly area or copy a poly area from desired object part, and put it in a seperate layer, and parent that layer to the main object.

Greenlaw
10-22-2015, 04:12 PM
A simple workaround is to cut out the polygons that you want to emit particles from and save that as a separate emitter object. You can parent it to the original object and use Unseen By Camera to hide the polygons from render. If this is part of a character, you'll of course want to use Use Bones From instead.

If you really need it to work like a weight map, you can use a texture mask instead. Set it to emit from Object Surface and put your texture in the T button for Birth Rate. If you're using a planar mode, I recall you need to set Width and Height to Edge. I'm not 100% sure but I think the result is single bit, so if you use a gradient image, the particles may only emit from a 'high-con' version of the image. I don't know for sure if it works with UV mapped objects but it should. It's been a very long time since I had to do this but I think that's accurate.

As for why there is no support for Weight Maps in ParticleFX, it's as prometheus explained. This tool is about 15 years old, the original developer is no longer attached to NewTek, and it has only seen very minor updates over the years.

I think LW3DG is probably looking towards creating a more modern particle system than updating this one. The current Flocking system may be an indication of the direction they are going in but that's just my speculation. Personally, I'm hoping that they will go with a nodal approach.

G.

jeric_synergy
10-22-2015, 06:19 PM
On a positive note, Weight Maps are not as animatable as texture maps. You can have a "video" of a circle moving about and use that as the emission area-- that's pretty darn flexible.

Still, a significant oversight.

Greenlaw
10-22-2015, 06:29 PM
You're right! This feature had been broken for the longest time--I remember trying to use an image sequence as a spray emitter on wave crests for a movie about 15 years ago but it never worked consistently. I believe I read that LW3DG finally fixed this feature not too long ago. (I haven't needed to revisited this feature myself yet but I might have to try it just for the heck of it.)

So it appears they are still updating this tool...a little bit anyways. :p

G.

jeric_synergy
10-22-2015, 08:34 PM
Just for fun I started to put together a demo of this, but it might still be broken. :(

And, in fact, some things in PFX don't seem to be working: SHOW SIZE, for example, doesn't seem to respond to changing the size.

More later.
+++++++++++++++
I got it to work, but it crashed Layout during the Package process. You'll have to make do with one image (you may of course create your own sequence).

Works, but my advice is:
get it working w/ONE image first,
keep your image rez low, because that really REALLY seems to slow things down horrendously. I have a sneaking suspicion that Layout loads the entire image stream into RAM, and the app slows to a crawl.
crank up your BIRTHRATE-- in fact, the effect is not a NOZZLE setting, it's a BIRTHRATE setting, a little like weights in the Instancer.

Since I didn't include an image sequence, you can make your own or just animate the single image using envelopes.

Oh, and SHOW SIZE doesn't show the size (THANKS, developer! :grumpy:) but OUTPUT SIZE does.

130500

130501
+++++++++++++++++++++++++

Here's the rest of the very simple animation sequence:
130502

jeric_synergy
10-22-2015, 10:52 PM
Now, even though this works, some particles ARE generated away from the white part of the image sequence.

Should I report this as a bug?

JoePoe
10-23-2015, 12:10 AM
Now, even though this works, some particles ARE generated away from the white part of the image sequence.

Should I report this as a bug?

NO bug.

Your image wasn't completely black: R=1 G=1 B=1
Changed it to 0,0,0.
All is well.

130503

jeric_synergy
10-23-2015, 01:00 AM
I wonder how that happened? In AE, it's listed as 0/0/0.

That is: the comp is set up to be 0/0/0 , the render added 1.

Farhad_azer
10-23-2015, 01:03 AM
Jeric is right that textures are more animatable but what if we are dealing with non planar objects? cut/paste will also be limited bec the original obj may be bending and deforming and this might be extremely difficult (if not possible) by procedures that Greenlaw mentioned.

Again not super duper important for now but only weightmap in particle emitter would have made things a lot easier.

I am also curious if it is impossible for current LWG team to add sth new (for example for this particular issue) even if the original developers are not active anymore? might sound stupid but the original codes are not invisible and some new stuffs could be added. correct me if I am totally wrong please.

jeric_synergy
10-23-2015, 01:09 AM
The projection can be UV, so it can conform to the mesh.

JoePoe
10-23-2015, 01:13 AM
Jeric is right that textures are more animatable but what if we are dealing with non planar objects?

How about a UV map? Animate your sequence within the UV space.

Ha! Beat me.

pinkmouse
10-23-2015, 01:54 AM
I am also curious if it is impossible for current LWG team to add sth new (for example for this particular issue) even if the original developers are not active anymore? might sound stupid but the original codes are not invisible and some new stuffs could be added. correct me if I am totally wrong please.

Hopefully they are spending their time developing and entirely new system for 2016. :)

Thomas Leitner
10-23-2015, 02:11 AM
The projection can be UV, so it can conform to the mesh.

NO!
UVs donīt work in PFX. I made a bug report 3 years ago. They confirmed the bug but never repaired it.

ciao
Thomas

jeric_synergy
10-23-2015, 08:59 AM
Contemplating testing this, but then was confused: is it the UV projection of an image that's not working? Or is particle emission dependent on the UV value assigned to a point?

That is: if the UV value is 1.00 it regulates birthrate.

JoePoe
10-23-2015, 09:05 AM
Contemplating testing this, but then was confused: is it the UV projection of an image that's not working? Or is particle emission dependent on the UV value assigned to a point?

Tha latter.
Nope. Don't work.
Guess the PFX system doesn't like any type of input relying on individual vertex info, period. (get it... a period is a point :D)

prometheus
10-23-2015, 09:11 AM
A simple workaround is to cut out the polygons that you want to emit particles from and save that as a separate emitter object. You can parent it to the original object and use Unseen By Camera to hide the polygons from render. If this is part of a character, you'll of course want to use Use Bones From instead.


I think LW3DG is probably looking towards creating a more modern particle system than updating this one. The current Flocking system may be an indication of the direction they are going in but that's just my speculation. Personally, I'm hoping that they will go with a nodal approach.

G.


thatīs what I said, copy and paste geo on to another layer:D

I am not that fond of the flocking system, since I have no realtime feedback on how they move on till it is calculated, I hope they can improve on that in such case or add a completly new particlefx tool, I would like to keep the ol particefx live playback if possible.

Regarding nodal particle fx..sure, that will expand on power of things, but I am not sure I would like it to abandoned, the simpler old particlfx module container and texture button to set it up is very easy, in fact..when looking at how you set up a birth rate texture emission in lightwave VS modo, lightwave wins in ease of workflow to get started..while it is more cumbersome and no so easy for "ordinary" folks to get started with nodes and set a birth rate emission by texture up in modo..seen it and I didnīt like it particulary, but it does indeed offer more power in terms of connectability.
Not sure if we both can have the cake and eat it in this case?

jeric_synergy
10-23-2015, 09:17 AM
OK, although if it did work, that would be a perfect standin for weight maps.

OTOH, modulating the birthrate by UV value seems weird to me: it's a scalar value, and the UI for it is pretty convoluted. In what circumstances would this be convenient?

(I whipped up a texture projection just now, and it works fine, except that playback will not stop - VPR is on.)

for noobs: it's not the location of emission you are adjusting here, it's the birthrate from the several choices of location - surfaces, vertices, edges, etc. So, reminiscent of Weighting as used in the Instancer.

prometheus
10-23-2015, 09:20 AM
another tip..we have mentioned emitting from objects, but you can divide a proxy object select points from that object and set emitt by vertices, in fact you can use weight paint for an object and paint where you want emission, then select points based on that weigthmap, and copy and paste those points to a dedicated point emission layer.

so if you have an asteroid, I would copy that geo and divide it a lot, paint a weight map where I want emission, select points by selection tab and menu maps/by vertex map value...copy those points and paste and name to emission point layer.


130512

jeric_synergy
10-23-2015, 09:23 AM
I've had very little luck selecting by weightmap, although it's probably pilot error.

prometheus
10-23-2015, 09:26 AM
I've had very little luck selecting by weightmap, although it's probably pilot error.
check my image I edited in previous post...it all depends on how you set your value..you got to know the tool, yes..probably to little flying time:)

Greenlaw
10-23-2015, 09:26 AM
I'm not too surprised.

ParticleFX was originally developed as a third party tool before LightWave even had UV map support. Yes, the FX tools are that old! It's remarkable that the FX suite can still be so useful, essential even. Can you imagine LightWave without .mdd support?

Sadly, when ParticleFX was purchased and added to LightWave (back in version 6?) it saw very few updates. It still does a lot of cool stuff but it's also only doing what it did 10 - 15 years ago. I'm glad to have it when I need it but we really need something better.

For me, the really big limitation with ParticleFX is the number of particles can reasonably handle. Because of that, I've mostly been using the 3D Particles in Fusion or TrapCode Particular in AE for the past three years. It's so much faster too. I've mainly used it for blood, water, oil, smoke and fire effects.

I still use PFX occasionally but only when I absolutely can't get the results I need out of particles in Fusion or AE.

Flocking, on the other hand, is fairly new and still being developed. It's super cool but obviously not meant to be used as a general purpose particle system.

G.

prometheus
10-23-2015, 09:32 AM
I'm not too surprised.

ParticleFX was originally developed as a third party tool before LightWave even had UV map support. Yes, the FX tools are that old! It's remarkable that the FX suite can still be so useful, essential even. Can you imagine LightWave without .mdd support?

Sadly, when ParticleFX was purchased and added to LightWave (back in version 6?) it saw very few updates. It still does a lot of cool stuff but it's also only doing what it did 10 - 15 years ago. I'm glad to have it when I need it but we really need something better.

For me, the really big limitation with ParticleFX was the number of particles can reasonably handle. Because of that, I've mostly been using the 3D Particles in Fusion or TrapCode Particular in AE for the past three years. It's so much faster too. I've mainly used it for blood, water, oil, smoke and fire effects.

I still use PFX occasionally but only when I absolutely can't get the results I need out of particles in Fusion or AE.

Flocking, on the other hand, is fairly new and still being developed. It's super cool but obviously not meant to be used as a general purpose particle system.

G.

yes ..particle amount handling would be a nice new improvement, I think I could do some seriously cool particle effects and others as well with increased speed of "cooking" the particles at a level at 6-8 millions...today I can go to 3 millions with acceptable cooking..but 6-8 millions it starts to overcook in time..and at some point it might end up on memory too...it also depends on hardware and memory of course, not sure if they would need to adress it with similar tech as krakatoa does, and no..the krakatoa developers has made it clear that Lightwave isnīt in the planning for any support...yet.


https://www.youtube.com/watch?v=OYpvZyikRqY

Thomas Leitner
10-23-2015, 09:36 AM
Contemplating testing this, but then was confused: is it the UV projection of an image that's not working? Or is particle emission dependent on the UV value assigned to a point?

It is the UV projection of an image that's not working. You canīt use an UV projected image to control birthrate.

ciao
Thomas

prometheus
10-23-2015, 09:42 AM
One would think that for some smart coder..it canīt be that hard to fix weight map emission? or maybe it is..maybe require to rewrite the particleFX completly or add code to that which only the lw team can do?
pawel olas made his own particle system..but it is limited to his fire and smoke system, so some stuff it canīt acess.
http://www.polas.net/smoke/

Hypervoxels can get acess to painted weightmap..if you want to paint in hypervoxels in certain areas..but that is a different thing, the toolset for that is a bit awkward scattered in the UI since you canīt acess it directly in the hv panel.

prometheus
10-23-2015, 10:52 AM
Actually..the node wizzard Bryan Phillips (bryphi77 on youtube) has proven that we can emitt from weight maps with node trickery.
I have suspected it should be possible..tried it, and had no Idea how, so I gave up and thought it might not be possible until someone proves it possible...and here you go...


https://www.youtube.com/watch?v=eU_I-Rt2VfQ&feature=em-uploademail


one thing about Bryan..he seem to rarely jump in and notify in threads, so that is a reason to subscribe to his channel and follow him, be patient..his tutorials can be a bit long perhaps, but you can learn a lot.
To work with it like this requires tweaking and experiment and isnīt very user friendly..but it seem to work in terms of end results.

might be possible to compile in to a compound node for easy load in to the node system.

Thanks Bryan.

Farhad_azer
10-23-2015, 12:47 PM
Thank you soooo much Michael, I again am going to sleep late.

Bryan has awesome tutorials and I wish he will change slightly his way of representations. I hope he will not be insulted and this is my humble opinion.

I really believe dpkit should be internalized. look how much we are missing without these tools.

High five Michael.