Smoke with fluids

[eyesickle]

I am trying to create a smoke stack on a steam engine that moves along a curve. I have been successful at creating different types of emitters, but many of them only emit for 55 or so frames. The emitting stops and the 3D fluid container stops following the emitter. I have one version that exists throughout the cycle (2400 frames), but I have been unable to control the emitter well enough to use the scene.

[Anonymous]

Not sure why your emitters are only emitting to frame 55.  May need more information, but have you checked the following?  

1. Make sure your timeline is the proper length.  2. Check the keys on all of your emitters (if there are any) 3.  If you're emitting from particles check lifespan 4. look at "max count" under the Emission Attributes tab. Make sure this is set to -1 5. Make sure that your emission source isn't moving faster than the fluid container

The fluid should follow as long as there are voxels being populated with some sort of emission. 

[eyesickle]

I like the behavior of the container. I ended up copying the container and
spreading the copies down the timeline. I really like the look and the
speed.

Now I am faced with rendering. It seems you cannot break up the rendering
due to the process of fluids. Currently I am trying to allow the fluid to
compute (in wireframe), up to a good point in the timeline to assign a
portion of the render.

I have read about caching, but haven’t tried it yet. It seems data heavy

[Anonymous]

Particle effects, which I am assuming you are using take time to "build up". To start at 0 vs frame 55 you could set your timeline to -55, or maybe -53 " give it a couple frames... I think that solves your problem of starting so late in the animation.

As to your second question, any particle effect (including fluids), does need to compute straight ahead, there is no option to backtrack, or start from a given point. Caching will solve some issues, and is lighter on the machine than trying to compute as it renders. There are options to convert your fluids to geometry, etc after the simulation is complete as well. It all depends on your situation.

In the case of a puffing train I would only do one simulation, convert the simulation to polys, cache it, etc, and attach that singular simulation to each time the engine should puff.

Other solutions would include rendering the effect separately and compositing it in post, etc.

Hope I gave some insights.