Add “Layer Color Mixing” (Striped Optical Blend) mode to automate per-layer tool/filament alternation

[DayA9-Max]

Is there an existing issue for this feature request?

• I have searched the existing issues

Is your feature request related to a problem?

Many multi-material users want colors they don’t physically have (e.g., pink from red+white) or want intentionally “blended” aesthetics (like the green-looking purge block effect from layered black+yellow). With FDM, this is a known visual phenomenon (color assimilation / “Bezold spreading”-type effect) when you alternate thin stripes/layers.

Right now, achieving this in Snapmaker Orca requires:

• manually adding many layer-based “Change Filament/Tool” operations (impractical for hundreds of layers), or
• exporting G-code and running external post-processing scripts (hard to preview, fragile, and not beginner-friendly).

This is exactly the kind of workflow that benefits from first-class slicer support.

Which printers will be beneficial to this feature?

Klipper

Describe the solution you'd like

Add a built-in slicer feature that automates layer-based tool alternation specifically for optical color mixing.

Proposed feature name(s)

• Optical Color Mixing
• Layer Color Mixing
• Color Assimilation Mode
• Bezold Blend Stripes (fun, but might be too academic—“Optical Color Mixing” is clearest)

User workflow (simple)
In the filament/tool settings (near “Change Filament at Layer”):

Optical Color Mixing

• Tool A / Tool B: dropdown (e.g., White + Red)
• Layer range: start layer / end layer (or start Z / end Z)
• Pattern ratio: A:B (e.g., 1:1, 2:1, 3:1, custom)
• Scope:
  • External walls only (recommended default)
  • Whole part (eliminates waste if purged into infill)
  • Top surfaces only / bottom surfaces only (optional)
• Toolchange handling (U1-specific default):
  • Use standard U1 toolchange macro + prime (same as existing multi-tool prints)
  • Optional: standby temperature for inactive toolheads

Expected behavior

• Slicer emits deterministic per-layer tool changes according to the selected pattern.
• Uses U1’s normal toolchange/prime routine so prints remain reliable.
• Preview should clearly show tool usage (colors per layer), making it safe to iterate.

Describe alternatives you've considered

1. Manually adding dozens/hundreds of “Change Tool at Layer” entries.
2. External post-processing scripts to inject tool changes and prime logic (works, but fragile and hard to validate).
3. Painting or model-splitting and gluing (time-consuming, defeats the point of automation).

None of these provide the “it just works” experience that Snapmaker Orca could deliver, especially given U1 hardware capabilities.

Additional context

This is a high-visibility differentiator for U1.

Optical layer mixing is a “wow” feature that is:

• easy to explain in marketing/docs (“print new colors you don’t own”),
• easy to demo (small swatches showing pink/purple/orange effects),
• uniquely enabled by the U1’s fast tool changes and dedicated heads.

Example use cases

• Generate “pink” from red+white, “light orange” from red+yellow, etc.
• Decorative textures on boxes, signs, figurines, organizers, gift items.
• Branding, labels, and subtle gradients without needing special filament.
• Controlled aesthetic striping as a design element.

Implementation-friendly acceptance criteria

• User selects Tool A/B, layer range, ratio.
• Slicer generates tool changes at layer boundaries accordingly.
• If the printer profile supports it (U1), toolchanges include prime/standby logic consistent with existing multi-tool prints.
• Preview reflects the mixed-mode tool plan.

Also helpful for any multi-tool / multi-extruder printers, but the U1 stands out because:

• tool changes are fast and repeatable,
• each filament has a dedicated toolhead (no cross-contamination),
• tool changes can include predictable prime/standby macros.