Smoke - Start/Stop/Start

Support Particles and Physics Simulations
1

Greetings. I’m hoping for advice that might save me a bunch of time.

My animated character has a coffee cup in her right hand and a cigarette in her left.

She has a sip of coffee and sets the cup down, and I want the cigarette to emit smoke during that time.

Then, she takes a drag from the ciggie.

The emitted smoke would stop - but the prior smoke would continue to rise.

Then, she moves the ciggie away from her mouth and the smoke emission would resume.

I would imagine that I could keyframe the Flow in some way, but I’ve not found a good tutorial on how to do that.

Thanks in advance for any ideas,
Cal

2

On the smoke emitting object, you can go into the fluid settings and animate the “density” setting to stop and restart smoke.

(Assuming you are using smoke simulation.)

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3

OK. Cool. That will get me started. Thanks.

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4

Hi. Me again.

I watched a couple tutorials and tried them as test projects. Everything OK - I’m at 3.3.5, Windows 10.

Then, I tried to do the same thing in my project. And it did not go well. (My project is about 30 MB)

The emitter is a cone and is parented to my cigarette. My cigarette is a “Child Of” a finger bone of my animated character, so… it moves.

I will need about 250 frames for my idea to work. If I’m an idiot, please tell me.

Anyway…, when I click “Bake All” in the domain, the progress shows that it gets about 15 frames - and then - Blender stops functioning. It does not disappear. It does not say “Not Responding” in the title bar. Task manager says CPU is active but just 50 %.

Thoughts?

Thanks,
Cal

5

What is the resolution of the domain? It just sounds like the simulation might be too much.

As far as I know, Blender’s smoke is not multi-threaded, so it’s normal that your CPU is at 50%, I get 50% too when baking smoke (including when it works correctly). The simulation still might be overwhelmed by too much resolution.

Make sure the domain isn’t bigger than it needs to be in the scene and progressively increase the resolution to see what your computer can handle. Don’t forget, the resolution applies in 3 axes, which means that when you double the number, you actually increase the number of cells by 8x (2x2x2), so it adds up quickly.

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6

Thanks, it was way larger than needed. The crashing has stopped.

However…

I may have to convince my viewers that she is smoking an ECigarette and call it “good enough”.

This is probably the root cause of my problems - something that can only be solved by spending lots of money. I’ll start being extra nice to my wife and see what I can arrange. :rofl:

Again, thanks.

7

Well, the smoke simulation might not be lost yet.

An other thing to check is the noise feature. Are you using it and if yes, at which level? For fine, whispy smoke, it can help get a finely detailed look, but make sure not to give it more levels than it needs or it just becomes a performance drain (anything past 3 levels makes little difference).

you might also still be able to work with a lower resolution if you have a nice smoke material. You can make smoke look a lot more detailed by making it hollow, like in this video.

If smoke sim doesn’t work, maybe an alternate, lighter way of faking smoke could be used instead, like a procedural material?

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8

Thanks for the encouragement! Now I know why I never dreamed of Majoring in Physics.

Let’s write an Add-On called Smoke For Dummies. It has 2 sliders

  1. Steam <-------------------> Canadian Forest Fire
  2. Small <-------------------> Big
    And a color wheel.

I was a softwqare engineer. When frustrated, I would walk away from it and go have a cigarette. Often, my best solutions were realized then.

I was trying to walk away from this project for a while, but I keep coming back - or watch tutorials and get inspired.

I’ll keep you up to date - until you tell me to stop.

Cal

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9

could have filmed the cig smoke during one of those breaks to use instead. :smiley:

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10

I have made some progress.
I used ideas from the “Steam” tutorial above and another tutorial about cig smoke.
I am able to bake 50 frames - but it’s a little frustrating.

Here’s some notes from this morning:
//*******************************************

domain
free all

save - close - reopen

bake - crash - blender disappears

reopen - bake - crash - blender disappears

reopen - bake - 94% - not responding - end task

reopen - wait for hard drive - bake - OK!

save - close - reopen - render - OK!
//*******************************************

So… I will continue trying. Thanks.

11

OK folks, … I’m giving up on this idea for now.

I’ve wasted way too much time on a mundane detail.

Thanks to all who replied.

12

I’m late to this party, but I second what @KDLynch said- use an animated image texture for the smoke and animate the visibility

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13

Did you see this new video yet?
The second option reminded me of you. You don’t need super detail in wispy or exhaled smoke.

Nobody has mentioned OpenVDB. There may be some that fit your needs.

… when you come back to this.

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