[Steve Bentley]

It depends on what you consider acceptable. The built in Thinking Particles and Pyro Cluster can only get you so far – a kind of blurry smoke or a fluffy smoke that’s hard to control. The problem is the sheer number or particles or voxels needed and the type of render engine and the control you have over both.
You can get better results with Xparticles. (at least if you are after realism or control)
You can amp up your game even further with Krakatoa and Turbulence FD – these are made for this purpose.

But all of those are $500 plus at last check.

Houdini is built for this kind of thing too but often you have to add another render engine (the same goes for C4D- you can use Krakatoa: an engine designed to handle the huge number of particles needed. I think the built in C4D renderer and Octane would be pretty close, plus for this, Octane might be a bit too slow and you might have a lot of noise, but Octane will still need a better particle system than TP).
The other issue with Houdini is it doesn’t so much have a “learning curve”; more a “learning wall” – I have the bruises on my forehead to prove it. But it is the king of doing any kind of particle work where you want a lot of control. I love it because it’s easy to turn off just the one particle when the director says “get rid of that one right there!” I’d hate to be a pet store owner when he’s picking one goldfish from a tank of 2000.

But there is another great alternative. Blender. Its a little different to work with if you are experienced but if you are new to the whole game you might take to it right away. And its free!!! And Smoke is built in!!!
In blender, to make smoke, you make a box, apply Smoke and hit play. (Ok, that’s a little over simplified but not by much)

[Steve Bentley]

Can you be more specific? What time in the in the video? There are all sorts of “effects” going on there.

[Steve Bentley]

Its a bit of a cheat. (but aren’t all effects!). It just one shape (the arrow) moving in a straight line but disappearing/reappearing; either disappearing behind a diagonal matte or reappearing from behind a curved mask.

I think what really sells it is the tip of the arrow barb that is disappearing getting cut off by the emerging arrow, before the point runs behind the mask. It gives some motion to the corner turn which is happening only in your brain and not on the screen.
There is also a mask you can’t see that reveals the barb as it emerges from the curved mask.

To achieve the endless loop just set up a single arrow and your masks so the arrow travels in one direction – then use the offset effect (down at the bottom in Utilities I think) and let the arrow run off one side of the screen and back on the other so that there is just a bit of space between head and tail. Then precomp all that and use it as an element and rotate it by 60 degrees and do that two more times.

The thin band of nothingness that is part of the curved mask is essential so the brain sees the negative space and associates that with a conveyor belt or roller type structure.

[Steve Bentley]

And the shadows of course – the new engine might look after the hair’s AA but the shadows the strands casts still need a high AA rate to keep them from being too noisy.

[Steve Bentley]

The high AA is for the rest of the objects – there’s some deep noise textures that get a little to chattery on lower settings.
Today I’ve been rendering the hair alone in groups with shadow catchers and alphas – so far no jumping. The jumping was only on the objects that were clones but have since been flattened to geometry, and they rendered for many frames before suddenly looking like something from Jacobs Ladder.

[Steve Bentley]

Thanks Walter, quite right (old habits die hard).
Here’s something I hadn’t noticed before. I have a QT movie that was rendered out of AE. The work area spanned frame 2000 to frame 3000.
If I bring that movie back into AE and let it generate its own comp, that comp starts at frame 2000. If I change that so that the comp starts at 0, when I engage time remap, the first keyframe’s value is 2000 even though the keyframe is sitting at time 0.
I don’t remember QT having a frame number memory. And I can’t believe I’ve not noticed this before.

[Steve Bentley]

It depends on the cloud look you want. Personally I like the look of vinyl paint, but acrylic works too(with acrylic extending medium). I find water based ink starts to dissolve in the water too quick so the cloud starts to blur right quick. I’m also not a fan of black ink. It works great for stock footage but you don’t see the subtle density differences or the shadows in the folds – it just ends up looking like a matte of itself.

[Steve Bentley]

Right click the footage and choose Time/Enable time remapping.
This will put a keyframe at the beginning and end of the footage, representing the first and last frame. Goto the frame where you want the slowdown to start and add another keyframe. Then drag the end keyframe out to where you really want the clip to end. You can also now extent the layer out to that point or there will be nothing to see – make sure to make your comp long enough.
In the curve editor you can alter the way the new speed eases into being.

This may not be the best, depending on the footage (but it is the fastest) as it won’t give you those inbetween frames that weren’t there to begin with. For that you need the Time Warp effect which you can choose “Source Frame ” and Pixel motion for how it interpolates and that will make up frames that weren’t there that are needed in the slow down. Use same idea as the Enable Time remapping; tell the SourceFrame keyframes what frame of the clip you want to appear at what time.
You can also use third party plugins like Twixter.

[Steve Bentley]

Well so much for that. Everything looked good, test renders at low AA rates were fine. But once the big render started at 2 and 8 sampling and Gauss. It all fell apart. Initially all the “hair” looked good but then about 100 frames in, the hair started changing (no dynamics and even the world gravity is turned off) – hair clumps would pop off here and there, change places, seeming geometry changes but it might just be generating the hair cluster again. Even editable plane geometry that is visible and also being used as a generating surface for a few clumps of hair would turn off during the render – the plane itself would become invisible.
Before, I was putting hair on cloned objects but it seems the clones are generated every frame so to the hair, so every frame was different. So I ended up “flattening” every object that is a hair generator and figured it was solved.
The Issue seems to build up as the render goes along. Am I asking to much of memory? (128GB)
If I render later frames as singles it all looks good. If I render the problem frames as singles it all looks good. Does an error build up or is there a memory leak with hair?
I’m going to try rendering each set of hair separately and see if I can get away with that and comp it all together.

[Steve Bentley]

Hey I didn’t know you could drag and drop the HUD items. I’ve just been right clicking on the attribute I want (the enable check box for instance) and selecting “add to HUD”. I always get two copies of that thing in the view port.