Hi Guys. Recently I’ve been trying to get a convincing cigarette smoke and so far I’ve gotten pretty good results. I’m using particles affected by turbulence and rendering them as a point density texture mapped to volumetric cube. It seems the best way to go. The only thing I’m not figuring out is how to make the particles dissolve eventually instead of simply dying suddenly.
Does anyone have a tip?
I reeeeeeeeeeeeeeeeeeeeeeeeeally want to know that too.
There seems to be plugins like re:ticular (I am trying hard to solve it with what comes in blender though, so I did not test it yet) and you could animate the scale of the particles creating a texture in the particles tab, applying a blend gradient to it, setting it to affect the size and setting the coordinates to “strand/particles”. That way the scale will run trough the map and go from black to white, big to small.
It is a fantastic sollution they gave to the particles properties, but it curiously work only on them. You can apply a gradient in the opacity and set the coordinate to strand/particles and it will do nothing. The over all color will stay in the middle of the gradient.
I am thinking of posting a new topic, but let’s hope you get some attention.
maybe you should try using the smoke simulator? it has some better controlls for dissolve and should look much more realistic than particles
I haven’t been able to achieve a nice result with this. You see, to make a nice slow and steady stream of smoke with really nice details you need to use and absurdly huge resolution which makes it impossible to bake. But with particles it’s quite easy to set up to look great. it just won’t dissipate. 
I hope this gets more attention…
Particle got BORN (birth and appear), LIVE up to certain time and DIE (disappear). These all defined by Particle Lifetime.
Like I said:
“It is a fantastic sollution they gave to the particles properties, but it curiously work only on particle properties. You can apply a gradient in the opacity and set the coordinate to strand/particles and it will do nothing. The over all color will stay in the middle of the gradient.”
Yup. But there are many other situations where you need something related to somke, but don’t want to use the smoke simulation Blender MUST have some way to controle textures with the particle age. This is basic in any particle system.
The closes I’ve come to solving the opacity problem (and barely only that) is using the volume material with point density, and setting the density to very low. Then, when there are many particles it will be opaque and with less particles it will fade.
Of course, this is very far from a good sollution. But it will have to do for now.
Yes, this the only solution I came up with. Still it does not work that well and to give fairly nice results I need to use a stupidly large amount of particles with a stupidly low density.
The particle system is sadly very limiting and it deserves a lot more attention… I don’t really understand why is it being so much ignored, especially when motion design is such a big part of the cg community.
Oh, but the current blender foundation project is our best hope. After all, what is VFX without particles?
I wonder what improvements will they create for that. After all, big buck bunny made the hair tools the pretty thing it is now. And I think particles are to VFX what hair is to furry cartoons.
Besides, blender particles already are amazing. I changed from max to blender in my current project precisely for how well blender handles particles in the simulation, compared to 3ds max.
But like most things in blender, on one side you have amazing points, better then the most expensive tools in the industry and on the other the lack of very basic stuff. Stuff that became standard in most softwares 10 years ago.
Time should solve it all.
Anyway, I sent a bug issue to the bug tracker. First time I did that. I have no idea what will come out of this.
We’ll see :). Please update if you ever get a response! For now I’ll use the low density trick you mentioned before.
That’s part 2 of a Blenderdiplom tutorial on how to fade out an object into particles. About halfway down the page, they describe the technique to fade particles over time.
They even say “This setting is actually a hack that was added by the developers of Blender because the current particle system does not allow easy access to the particle lifetime, so it’s something you just have to know and that’s not very straightforward.”
That is very cool to know but not really a solution to the problem.
The thing is that, then, blender DOES have the hability to control texture with particle age. But why would it work only in this hack, and not in the particle system?
But thanks for the answer anyway. Now we have another way to solve it beyond using particle sizes or point density. It might work in many cases.
edit:
Just to be clear, as far as I understood this only work when you are using the explode modifier and using the mesh faces as particles.
It would not work with normal instanced particles.
I did not find out how to solve this, but I am freaking happy with what I found.
I am almost glad for blender’s particle limitation and making me research this, since getting this result with real particles and age texture would have been a lot more difficult!
You can control a lot of things, like age opacity and so on with the point density in the volume material. And with the turbulence, it gets amazing without having to simulate anything again, and you get a lot of details without new particles.
I don’t think it works in animations, but I want to test it later.
It’s not the first time that blender’s lack of basic tools make me find out about amazing tools that I could not find in other applications. I doubt I could do this so well using 3dsmax. And I am not even considering its limitations with numbers of particles.
If anyone knows the developer of the point density texture, tell him how amazing someonelse’s life he made with this.
I haven’t been this excited about a new tool I’ve found for a long time. I hope to have a lot of fun with this point density/turbulence thing
And I woke up today to learn about another great thing.
Blender 2.64 test has been released, and it contains particle info for cycles!
I tested it and it works!
woooow, that is a great result!!! Could you briefly explain how did you control the fade out??
It is super simple. I attached a simple file to show.
You just create the point density texture on the cube surrounding the particles (with the cube pivot in the world center, just moving it in edit mode, I don’t know if you know this ugly thing ), set the point density accordingly to show the little sphere in the particles.
Then there are a whole world of funny options in the point density tab. One of them is the falloff, that you can set to particle age, and below it there is the falloff curve, so you can control it better.
In the wave I had to set the curve to veeeeery close to the bottom. Almost zero, since I wanted the volume to have a very big scatter, being very dense in one end. But I guess I am doing something wrong. But no matter. It works.
And be sure to play with the turbulence tab.
It is the most amazing thing on the whole point density stuff.
pointdensity.blend (547 KB)
I had to do this, in a hurry, without Cycles, with regard to a plume of smoke. And this is what I did …
(1) First, as is my custom, I generated the plume-of-smoke as a separate output that would be composited into the rest. (This allows me to control exactly how the smoke is going to integrate into the rest of the frame … to color it separately or what have you.)
(2) Having already decided which way the wind was blowing, and having neatly reduced the problem so that I could deal with “the smoke” in isolation from everything else, I simply spray-painted a separate black-and-white mask image. Then, I arranged for the node-network to use the “whiteness” of the image to regulate the Alpha of the smoke. Voila… disappearing smoke.
There is an obvious difference of approaches here, and I would argue that both of them just might be correct. The OP’s approach was to regulate what the smoke (particle system) truly is, in order to produce an outcome that is mathematically correct and therefore subject even to the most meticulous inspection. The other approach is to look only at what the final visual result has to “look like” and then to find the shortest plausible distance to get there by any means.
@guismo: This works great!!! Thanks for the help!! Now, I’ve been messing with the turbulence and unfortunately it only works for stills. It looks really bad while animated as if the particles are being masked by a cloud texture or something like that. But now I understand how to use the falloff option and this pretty much solves my problem.
Thanks!!! This feels like a new Blender feature for me, you can do all kind of crazy effects with this!
@sundialsvc4: Yes, this is a way of faking it. Unfortunately, for my case it didn’t look good. You could exactly tell where the mask ended…
@sundialsvc4: This would be a last, desperate attempt for me. It is not ideal but might work. But to many things it would not, or it would require a lot of extra work, like in this wave situation.
@spockless: If you get to animate something, try to share with us. I will test it sooner or later, but I wish to know how it turn out.
But I thought it would not work… That is a shame. You simply can´t get this level of detail without using billions of particles in the right way.
