Smoke Ring

Smoke Ring launches rings of smoke from an object, the kind a smoke cannon fires. Each ring rolls as it travels, widens and slows down, starts to wobble as it ages, and fades. Launched in pairs, one ring catches up, slips through the other and takes the lead, and then the two swap again.

How it works

The rings are simulated, not keyframed. Each ring is a spinning loop of air, and its own spin drives it forward; a wider ring travels slower. Every ring also pushes on the others, which is what makes a following ring shrink, speed up and pass through the one ahead, the leapfrogging seen in real vortex rings. The smoke sits mostly in the core of each ring, turning around it, with a thinner halo trailing outside that shears into a spiral. As a ring ages, a wave grows around its circumference and it begins to wobble.

Settings

• Ring Count: rings alive at once, up to four.
• Interval Seconds and Rise Speed: how often rings launch, and how fast.
• Expansion Radius: how far they travel before fading.
• Thickness: the thickness of the smoky core.
• Leapfrog: launch rings in pairs that pass through each other.
• Wobble: how strongly older rings wobble.
• Smoke Color.

Use it for

Smoke cannons, dragon breath, magic, calm looping backgrounds and playful product moments. Compare Smoke Plume for a rising column and Shockwave for an outward blast.