Mask Scatter

Overview

Places stamps on pixels that pass a mask threshold. It can repeat one image or mix several candidates at ratios such as grass A 70 / grass B 20 / flower 10. Center spacing, ground anchors, Y draw order, and tile-edge wrapping are handled together.

Usage tips

• Start with placement=Random when occasional clusters are desirable. Switch to KeepApart only when grass, stars, or stones bunch up too heavily. Existing projects remain on Random and keep their previous result.
• min_distance measures center-to-center pixels. Around 3px lightly reduces clusters; around the stamp width greatly reduces overlap. If the node warns that Count did not fit, lower the gap or enlarge the mask area.
• Connect List Create(Image) to Stamp Candidates and an equally sized List Create(Float) to Candidate Weights. Leave weights disconnected for equal chances, or use 0 to exclude one candidate.
• For grass, trees, or characters, combine anchor=BottomCenter with draw_order=BackToFrontY. Roots and feet land on the mask point while lower objects naturally cover higher ones.
• For seamless tiles, enable wrap_x / wrap_y. Overflow pixels continue on the opposite edge, and Keep Apart also measures center gaps across that seam.
• Variation parameters are the key to a natural result. random_flip with scale_jitter around 0.3 and brightness_jitter around 0.2 removes the copied look. Random Flip includes vertical flips, so leave it off for grass or characters whose base must remain upright.
• The range mask determines the effect. Use path_mask to place grass on the shape of the ground, or threshold a coordinates Y gradient to limit placement to an upper or lower region.
• Mask values are not density weights. Every candidate that passes the threshold has the same selection probability. Set alpha_enabled=false to use RGB brightness.
• Drive seed with seed_range to compare different scattering patterns.
• With no stamp connected, the node uses a 1px dot. That is often enough for stars or gravel.
• Changing only the weights does not change positions, flips, rotations, or sizes, so material ratios can be compared on the same composition.

Related nodes

• path_mask — the go-to way to define the scatter area
• seed_range / variant_select — generate different scatter patterns
• blend — composite the scattered result over a background
• path_array — regular placement along a path instead of random scattering

How to use

• Basic use

  • Connect the Path Mask output to mask.
  • Set the amount with count.
  • Change seed to change the distribution.

• Avoid clusters

  • Change placement to KeepApart.
  • Try min_distance=3–5 for small stars or gravel, or roughly the stamp width for grass and wood knots.
  • On tiles, wrap_x / wrap_y makes centers across opposite edges count as neighbors and continues overflow stamp pixels on the opposite side.

• Mix several appearances

  • Connect an image list to stamps and a list of the same length to weights.
  • [7, 2, 1] means roughly 70% / 20% / 10%; the values do not need to sum to 100.
  • Length mismatch, negative values, and all-zero weights are errors. Zero is useful for temporarily excluding one candidate.

• Threshold

  • 0.5 places stamps where the mask value is at least half.
  • A white + alpha mask such as Path Mask works as-is.
  • Values above the threshold do not receive a higher selection probability.

• Invert

  • When enabled, stamps are placed on the unfilled side.

Examples

Combine with Path Mask

[Multi Path] → [Path Mask] → mask → [Mask Scatter] → [Preview]

Scatter dots without a connected stamp

[Path Mask] → [Mask Scatter(count:32, color:white)] → [Preview]

Use any mask image

[Pixel Canvas] → mask → [Mask Scatter]

Create a natural cluster with variation

When batch-producing grass, stones, stars, or similar assets from one stamp:

[grass stamp] → stamp → [Mask Scatter(random_flip:on, scale_jitter:0.4, brightness_jitter:0.3)]

The same seed always produces the same result (deterministic).

Scatter two grass variants and a flower from their bases

[grass A] ─┐
[grass B] ─┼→ [List Create(Image)] → stamps ┐
[flower]  ─┘                                ├→ [Mask Scatter(anchor:BottomCenter,
[7,2,1] → [List Create(Float)] → weights ───┘               draw_order:BackToFrontY)]

Notes

• Two stamps are never assigned the same center pixel.
• The stamp images themselves can overlap.
• KeepApart guarantees center spacing, not footprint separation. Large, wide, or scale-jittered stamps can still overlap when larger than min_distance.
• If all requested stamps do not fit, the node outputs those that fit and shows a warning on min_distance.
• Only the center is guaranteed to lie inside the mask. A larger stamp footprint can extend outside it.
• The output dimensions match the input mask image.
• All variation is derived deterministically from seed.
• When Stamp Candidates is connected, it takes priority over the single Stamp input.