Fx Rasterize

Overview

Draws an FX particle simulation into an image. This is the first point in an FX lane where a visible image appears, and it also controls particle appearance, including color, stamp shape, and size.

Usage tips

• The output image is still raw. The standard flow is to finish it for pixel art downstream with palette_quantize and pixel_cleanup.
• Replace the shape of each particle with stamp—for example, turn a spark into a star or smoke into a puff. Only the stamp's alpha is used; its color comes from interpolation between color_start and color_end.
• Note the distinction between image (one current frame) and spritesheet (a raw preview). fx_bake_spritesheet creates the final sheet.

Related nodes

• palette_quantize / pixel_cleanup — the go-to downstream finishing nodes
• fx_bake_spritesheet — performs the final bake
• fx_emitter_2d / fx_force — upstream nodes
• outline — adds a finishing outline

Read this first

• Fx Rasterize is the first node that outputs an image.
• image contains only the current frame.
• spritesheet is a raw animation preview at this point in the graph.
• Connect stamp to use an image for particle appearance.
• The standard P11 FX workflow converts the state to an image here, then sends it through:
  • Palette Quantize
  • Pixel Cleanup
  • Outline

The role of stamp

• stamp is the image that defines the appearance of each particle.
• The image's RGB is ignored; its alpha/silhouette is used.
• The actual color is tinted with the interpolated color_start -> color_end color.
• size_scale and FxEmitter2D.size_min / size_max control the stamp size.

In short:

• To define emission positions with an image:
  • FxEmitter2D.mask
• To define the appearance of each particle with an image:
  • FxRasterize.stamp

Differences between image and spritesheet

• image
  • Contains only the frame currently being viewed.
  • Changing Preview Frame switches this single image.
  • Connecting it directly to Preview shows only the selected frame.
• spritesheet
  • Is a raw sprite sheet collected by evaluating Fx Rasterize once per frame.
  • The Inspector uses it for animation playback.
  • It still shows the appearance at the Fx Rasterize stage.

This node therefore does not send every frame through a single wire. Instead:

• image returns one current frame, while
• spritesheet returns the result collected by the backend after reevaluating every frame in sequence.

How to think about finishing nodes

• FxRasterize -> Outline -> Preview
  • Preview shows one current frame with an outline.
• FxRasterize -> Outline -> FxBakeSpriteSheet
  • Every frame receives the outline before being packed into a sprite sheet.

The natural distinction is:

• FxRasterize.spritesheet
  • for reviewing the raw FX animation
• FxBakeSpriteSheet
  • for producing the final sprite sheet with finishing included

Choosing a render mode

• pixel
  • Produces the sharpest result.
  • Draws square pixels.
  • Increasing size_scale creates 2x2 or 3x3 blocks instead of single pixels.
  • Best for sparks and splashes.
• blob
  • Best for fire and smoke.
  • Uses size_scale and softness.
• trail
  • Creates a trailing appearance.
  • Uses size_scale, softness, and trail_length.
  • Best for trajectory-like FX.

Larger softness values produce a wider, softer edge fade. trail_length multiplies the one-frame motion segment, so increasing it extends the trail farther backward in space.

Basic lane

FxDomain2D
  -> FxEmitter2D
  -> FxForce
  -> FxRasterize
  -> PaletteQuantize
  -> PixelCleanup
  -> Preview

Example

Flame-like settings

• render_mode = blob
• color_start = yellow
• color_end = transparent red
• size_scale = 1.2
• softness = 1.4

Spark-like settings

• render_mode = pixel
• color_start = white
• color_end = transparent yellow
• size_scale = 1.0

Understanding size controls

• FxEmitter2D.size_min / size_max
  • Base size for each particle
• FxRasterize.size_scale
  • Multiplier applied to all those base sizes

For example:

• size_min = size_max = 1, size_scale = 1
  • Approximately one pixel in pixel mode
• size_min = size_max = 2, size_scale = 1
  • Approximately a 2x2 block in pixel mode
• size_min = size_max = 1, size_scale = 3
  • Approximately a 3x3 block in pixel mode

Notes

• preview_frame is zero-based.
• The Inspector updates the preview_frame maximum to the connected FX frame_count - 1.
• Connected inputs take priority over color_start / color_end.
• For small pixel art, start with pixel or blob plus a small size.
• FxRasterize.spritesheet is a raw preview, so it does not include the result of downstream Palette Quantize or Outline nodes.
• Use Fx Bake SpriteSheet to combine every fully finished frame into one image.

Appearance when using stamp

• render_mode = pixel
  • Places one copy of the stamp for each particle.
• render_mode = blob
  • Places one stamp per particle instead of drawing a blob.
• render_mode = trail
  • Places copies of the stamp along the direction of travel to form a trail.

In this case:

• softness
  • Is not used.
• trail_length
  • Controls how far the trail extends in trail mode; stamps are placed along that extended path.

Example: using a droplet stamp

Small white silhouette image
  -> FxRasterize.stamp

Example settings:

• render_mode = pixel
• size_scale = 2
• color_start = light blue
• color_end = transparent blue

Each particle is drawn as an enlarged droplet stamp instead of a plain square pixel.