Light and biomes
This page covers two features.
- Light/spawn check: Shows the light level (0 – 15) of each cell as a color and marks cells where monsters can spawn. It also suggests light source positions that light up all spawn cells.
- Biome paint: Paints a biome map in 16×16-cell units onto the world. Grass, leaf and water colors follow the painted biomes, and Foliage chooses trees and grass that match each biome.
How to open
Section titled “How to open”| Feature | Where to open |
|---|---|
| Light/spawn check mode | Shift+L, or main toolbar mode row › Light/spawn check (if not visible, the More modes button at the right of the mode row) |
| Turn on light/spawn display only | Viewport bar › View mode › Light/spawn display |
| Light/spawn report | Tools › Light/spawn report |
| Auto light placement | Tools › Suggest auto light placement |
| Spawn cell list file | Tools › Export spawn cell list (json) |
| Biome paint mode | Main toolbar mode row › Biome paint (if not visible, More modes) |
| View biome colors only | Viewport bar › View mode › Biome color preview |
| Biome color renderer | Tools › Toggle biome tint (grass·leaves·water) renderer |
Quick start
Section titled “Quick start”Finding and lighting dark spots
Section titled “Finding and lighting dark spots”- Enter Light/spawn check mode with Shift+L.
- Press Midnight. Calculation uses the darkest time.
- The viewport shows light-level colors and red Xs (spawnable cells).
- Click a row in the panel’s warning list to go to that cell.
- Select a region and press Suggest in the Auto light placement section. Yellow ghosts show the light source positions.
- Press Apply. The light sources are placed. It can be cancelled at once as one undo step.
Painting biomes
Section titled “Painting biomes”- Enter Biome paint mode.
- Choose a biome from the biome list. Type a Korean or English name in the search field to find it.
- Drag across the ground in the viewport. The 16×16 cells touched by the radius become that biome.
- Grass, leaf and water colors change to match the painted biome.
Light levels and spawn cells
Section titled “Light levels and spawn cells”Brightness is the larger of block light and (sky light − time darkness). It is the same calculation as the in-game F3 screen.
| Display | Meaning |
|---|---|
| Color | 0 red → 7 orange → 15 yellow |
| Numbers | Writes light numbers on cells near the camera (when Numbers is on). |
| Red X | A cell where monsters can spawn. A dark X is a cell that is always dark regardless of time. |
Conditions for a spawnable cell (rules since 1.18): block light 0 · brightness ≤ 7 · a solid top surface below · 2 empty cells above. Changing the mob type recounts according to its body size.
| Mob | Empty space needed |
|---|---|
| Common monsters (zombie·skeleton·creeper) | 1 block wide × 2 blocks tall |
| Spider (3×3 space) | 3×3 wide × 1 block tall |
| Enderman (3 blocks tall) | 1 block wide × 3 blocks tall |
| Slime (slime chunk·y<40) | Independent of light. Slime chunks are calculated from World seed. |
Slimes cannot be blocked with light, so only a hint is shown instead of light source suggestions.
If you have drawn Regions with markers, spawn cells are counted per region. Spawn cells inside safe-zone or town regions appear in the warning list. For markers, see Markers, load budget and snapshots.
The block light, sky light, brightness and spawnability of the cell under the mouse are shown in one line at the bottom of the panel.
Auto light placement
Section titled “Auto light placement”Suggest finds the fewest light source positions that light up all spawnable cells for the current time and mob. They are shown as yellow ghosts and placed only when you press Apply.
| Field | Description |
|---|---|
| Lights | Torch (14) · Soul torch (10) · Lantern (15) · Soul lantern (10) · Glowstone (15) · Sea lantern (15) · Light block 15 (invisible) |
| Placement | Floor and wall · Floor only · Walls only. Only torch types attach to walls (they become wall torches). |
| Selection only | When on, only inside the selection; with no selection, the whole world is checked. On by default. |
The region checked at once can be up to 4 million blocks. Beyond that, a hint asks you to reduce the selection.
Export spawn cells writes the list of spawnable cells as JSON. It is meant to be read by server-side tools and never overwrites a file of the same name.
Biome paint
Section titled “Biome paint”Biomes are painted in 16×16-cell (chunk-width) units. The map is saved together in the world file (.npworld).
| Tools | How to use |
|---|---|
| Paint (drag) | Drag across the ground to paint. Shift+drag erases (back to the default biome). |
| Eyedropper | Picks the biome of the clicked cell. Ctrl+click while painting does the same. |
| Fill selection | Fills the cells of the selection with the current biome. |
Set all default sets the biome of unpainted cells to the currently chosen biome.
Color preview
Section titled “Color preview”Grass, leaf and water colors are read from the colormap in the target version’s jar. If there is no jar, default colors are used as an approximation.
| View | What it shows |
|---|---|
| Off | No overlay |
| Biome ID colors | Distinguishes cells with a different color per biome. |
| Grass color · Foliage color · Water color | Overlays that color of the painted biome. |
The small map at the bottom of the panel shows the biome cells from above (1 pixel = 16×16 blocks).
Tools › Toggle biome tint (grass·leaves·water) renderer (default on) draws grass, leaf and water blocks in the viewport with the painted biome colors. When off, they are drawn with the default plains colors.
Options
Section titled “Options”Light/spawn check
Section titled “Light/spawn check”| Option | Range | Default | Description |
|---|---|---|---|
| Display | Off · Brightness (with time) · Block light · Sky light | Brightness (with time) | Value shown as cell color. |
| Time | 0 – 23999 ticks | 18000 (midnight) | Game time. 6000 noon · 12000 sunset · 18000 midnight. Set it instantly with the Noon, Sunset and Midnight buttons. |
| Rain · Thunderstorm | On/Off | Off | Adds sky darkness from the weather. |
| Numbers | On/Off | On | Writes light numbers on nearby cells. |
| Spawn cells only | On/Off | Off | Hides light colors and shows only the red Xs. |
| Mob | General · Spider · Enderman · Slime | Common monsters | Mob to count spawn cells for. |
| World seed | Integer | 0 | Shown only for Slime. Enter the seed from the server’s level.dat. |
| Lights · Placement · Selection only | Table above | Torch · Floor and wall · On | Auto light placement values. |
Recalculate recalculates with the current world and updates the report.
Biome paint
Section titled “Biome paint”| Option | Range | Default | Description |
|---|---|---|---|
| Radius | 0 – 128 (steps of 4) | 16 | Brush radius (blocks). Every 16×16 cell touched by the radius changes. |
| View | Off · Biome ID colors · Grass color · Foliage color · Water color | Grass color | Type of preview overlay. |
| Tinted blocks only | On/Off | On | Paints grass color only on grass and the tops of grass blocks, foliage color only on leaves and water color only on water, to look realistic. |
| Cell borders | On/Off | On | Draws the borders of the 16×16 biome cells. |
| Blend | 0 – 7 | 2 | Radius of the game option “Biome blend” (2 = 5×5). |
| Cover | 0.2 – 1 | 0.8 | Opacity of the preview overlay. |
Shortcuts
Section titled “Shortcuts”| Key | Action |
|---|---|
| Shift+L | Light/spawn check mode |
| Biome: drag · Shift+drag · Ctrl+click | Paint · erase · eyedropper |
| Biome: [ · ] (or - · =) | Decrease · increase radius. Shift = larger step |
Console commands.
| Command | What it does |
|---|---|
light [time] | Prints the light/spawn report and goes to the first warning cell. time defaults to 18000 (midnight). |
lightplan [torch|soul|lantern|glowstone|sea] [both|floor|wall] [apply] | Suggests light source positions in the selection (or the whole world if none). Add apply to place them immediately. |
spawnmob <generic|spider|enderman|slime> [seed] | Changes the mob used to count spawn cells. For slime, also give the seed. |
spawnexport [file.json] | Writes the spawn cell list as JSON. Does not overwrite. |
biome <biome|list> [radius] | Chooses the biome to paint (e.g. biome desert 32). list = biome list. |
biomefill [biome] | Fills the cells of the selection with that biome. |
biomeundo | Undoes one step of biome painting. |
Tips / cautions
Section titled “Tips / cautions”- Biome paint undo is separate from block undo. Use the panel’s undo and redo buttons or
biomeundo. Ctrl+Z undoes blocks only. - Apply in auto light placement is a block edit, so a single Ctrl+Z cancels it all.
- The light/spawn check treats custom blocks (
np:) as opaque with light 0. Areas around light-emitting custom blocks may appear darker than they really are. - The mottled pattern of swamp grass is approximated with one color.
- After painting biomes, turn on Follow biomes in Foliage to plant different trees and grass per biome.
- Check shader-style lighting in Game view and shader pack.