Paths tab: Zones

Starting preset + Load preset - a whole system to start from: Rain, Snow, Stars, Fireflies, Insects, Bubbles, Dust motes, Embers, Fog wisps, Petals, Lightning, Coin rain, Water glints and Shooting stars. Loading one replaces the zones, the population, the motion, the cycle and the item and layer looks.

Start from the preset nearest to what you want and change one thing. Rain with the gravity turned negative and the bubble picture is bubbles; Stars with a flat ellipse over water is glints. The Atmospheric journey page lists what each one does.

A preset replaces your layers and drops any picture you uploaded onto them. Save first.

Name, On / Off, x - the name shows on the stage. Off keeps the zone in the design but no item is born in it. The last zone cannot be removed.

Shape - Rectangle and Ellipse use the position and size sliders below. Polygon uses nodes on the stage.

A rectangle for weather, an ellipse for a bush or a pool, a polygon for the odd shape around a lamp or between two characters.

X, Y, Width, Height - the zone's box in stage pixels. The stage is 1920 x 1080; the sliders go 400 px past its edge on purpose.

Rain wants to be born above the picture, so the drops are already falling when they enter: start the zone at Y = -260.

Polygon nodes - drag a dot on the stage to move it. Press a dot twice quickly to remove it (a polygon keeps at least three). Add node puts a new one in the middle of the longest edge.

Feather - the width of a soft band around the boundary. Fewer items are born toward the edge and none past the band. 0 is a hard edge.

60 to 120 px so a group of fireflies thins out at the edge of its bush instead of stopping at a line. Stars with a 120 px feather thin out toward the horizon.

Grow / shrink - pads the zone outward or inward without moving the outline you drew. The faint inner line on the stage is the shape you drew; the strong line is where items are actually born.

Draw the zone around the object on the screenshot, then grow it a little so items sit just around it, or shrink it so they stay well inside.

Spawn - Anywhere inside, or along one edge.

Bubbles from the bottom edge of a tank; embers from the bottom of the screen; leaves from the top.

Whole stage - makes the zone the full 1920 x 1080 rectangle.

Draw on stage - for a rectangle or an ellipse, drag the box out on the stage in one gesture. For a polygon, click its corners one by one and double-click (or press the button again) to close it.

Put the game screenshot on the Board tab first, then draw the zone straight over the bit of the screen where items will be seen. That is the point of zones: the same number of items in exactly the place they show, not behind the reel house.

Count - items alive at any moment. The field is always full: an item that dies is replaced at once, and with Infinite life on nothing dies in the first place.

350 drops for rain, 25 fireflies, 1 flash of lightning.

While a trail, sparkle or hit layer rides on the items, Count is capped at 24 and a note under the slider says so: each item then carries containers of sprites of its own. Mute those layers for a full field.

Lifetime - how long each item lives before it is replaced. Its curves, its picture sequence and the forces all run over this time.

4 s for rain, 8 s for snow, half a second for lightning.

Infinite life - items are never replaced. Each one keeps moving from where it was born for as long as the effect runs, so butterflies in a bush or fish in a tank do not vanish on a timer. Use it for anything that loiters; leave it off for rain, snow, sparks and flashes, which are meant to pass by and be replaced.

Fireflies or insects in an ellipse, with At the edge on Soft bounce so they turn back instead of leaving.

With it on, Lifetime is no longer a lifetime: it becomes the period of everything that runs over the life, so the item's Size and Opacity over life, its tint, a trail's length and a spark layer's emit window all repeat every Lifetime. A curve that does not end where it starts jumps at each repeat, and one that touches 0 blinks the item out once per Lifetime. The group tells you when that would happen and offers Flatten item curves, which sets Size and Opacity over life to a flat line; a curve that loops cleanly (the Fireflies twinkle) is fine as it is. Respawn greys out, and the Hit tab fires nothing, because nothing is born or dies.

Lifetime randomness - per-item variation of the lifetime. It also spreads the moments items are replaced, so a twinkle never marches in step.

Respawn - New spot: every life is a fresh item somewhere else, with new random draws (rain, insects). Same spot: the same item comes back where it was, with the same draws, so a looped opacity curve is a twinkle (stars, glints).

Greyed out with Infinite life on: nothing respawns.

Depth range - each item draws a depth: far items are smaller, move less and are dimmer. 0 is a flat field, 100 % is full parallax.

60 % turns flat rain into rain with depth. 80 % gives a star field its magnitudes.

Nothing is sorted by depth; at these sizes it does not show.

Size variance - how much each item's own size varies around the size you designed on the Item tab. Off means every item is the same size. The readout shows the range you get: 2 runs the field from half to double, 10 from a tenth to ten times, with as many small items as large ones.

2 for twenty butterflies or a swarm of flies. 1.4 is enough to break up a snowfall.

It is not Depth range: this only changes the size, while depth also dims and slows the far items. Only the item scales - a trail or sparks riding on it keep their own size.

Wander and Wander rate - a smooth random walk from birth: the large slow motion of a fly, a snowflake or a firefly. Turbulence is the small fast wobble; this is the big lazy one.

30 px at 0.3 Hz drifts like a snowflake; 140 px at 1.2 Hz darts like a fly.

Gravity + Drag - together they give a terminal speed, gravity divided by drag, and a note under the switch tells you what it is. Rain at 3000 with drag 3 falls at 1000 px per second and keeps falling at that speed; 7000 is a downpour at about 2300.

Negative gravity floats things: -300 with drag 3 is bubbles rising at 100 px per second.

Gravity direction - where gravity pulls. 90 is straight down; 75 or 105 is slanted rain at the same speed, 0 or 180 is sideways.

With Align to path on the Item tab the streaks turn with the slant by themselves.

Born at full speed - items appear already moving at their terminal speed instead of accelerating from rest. Rain, snow and bubbles want this on; a leaf let go from a branch wants it off.

It needs some Drag: without drag there is no terminal speed to be born at.

At the edge - what happens when the motion carries an item out of its zone's outline. The outline is the shape itself, grown or shrunk by Grow / shrink: for a polygon that means its slanted or zig-zag edges, not a box around it. Free lets it go. Wrap brings it back in at the opposite side of the shape, straight above or below where it left, so a rain or snow field stays full for ever with a fixed count. Kill hides it the moment it crosses the line. Fade is Kill with a soft edge: the item dims to nothing over a band inside the outline and is gone by the line. Bounce reflects it off the outline like a wall: rain in a box, a ball in a tank. Soft bounce turns it back before the line with no visible wall: the item slows as it nears the edge, turns and speeds up again on its way in, so fireflies and butterflies stay in their bush without ever looking as if they hit something.

Snow inside a shaped zone: Wrap for a field that never thins, or Fade with a 100 to 150 px band when flakes drifting out would look wrong stopping dead.

Kill and Fade keep a hidden item hidden until its life ends, so a field thins out; that is what Wrap is for. Wrap is for item-only fields: a trail layer on a wrapping item draws a streak across the shape when the item jumps sides.

Fade band - only with Fade: how far inside the outline the fading starts, in pixels. Deeper in than this an item is fully visible; it dims as it nears the edge, measured straight to the nearest line, and reaches nothing as it crosses. Trails, sparks and hits riding on the item dim with it.

80 px (the default) for rain streaks, 150 px for big slow snowflakes, 40 px for a swarm that should stay crisp almost to the edge.

Turn distance - only with Soft bounce: how far inside the outline an item starts turning back, in pixels. It slows into the turn, comes no closer than half this distance to the line and speeds up again on its way in, at its own pace: a slow firefly turns slowly, a quick bug quickly. Bigger is softer and keeps the items further from the edge; the tool caps it at half the zone's smaller side so the turn fits.

120 px (the default) for fireflies drifting at walking pace, 60 px for a quick swarm, 200 px or more for a butterfly that should seem to change its mind long before the edge.

The items never reach the line: a Soft bounce zone looks smaller than it is drawn by half the Turn distance. Grow the zone with Grow / shrink if the field should fill the shape.

On / Off - how long items are born, and the pause between windows.

Lightning: on 0.2 s, off 7 s. A flock of birds passing: on 4 s, off 30 s.

Randomness - varies each window's length and where it falls inside its period, so the timing does not tick like a clock.

Fade in / Fade out - items born in the first or last seconds of a window come in dimmer, so a shower builds and tails off.

Trigger cycle (header) - jumps the clock to the next window so you do not wait for it. Without a cycle it restarts the clock.

Depth - Behind the top elements draws the whole system under the pictures that sit between the board and the effect on the Board tab, the reel house (weather behind the reels). In front draws it over everything. Element 0 in the Board tab's stack moves to show it. The game gets this as a hint.

System seed - every birth point, lifetime and cycle window comes from it. Same seed, same field, in the tool and in the exported description.