Meshy 3D Printing

Prepare and send Meshy-generated 3D models to a slicer for 3D printing. This skill covers the full print pipeline: generating print-ready models, checking printability, downloading in slicer-compatible OBJ format, and opening in the user's preferred slicer software.

Prerequisite: This skill works alongside meshy-3d-generation. The generation skill provides the reusable script template (create_task, poll_task, download, get_project_dir, etc.) and environment setup. If the model has not been generated yet, use meshy-3d-generation first.

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Intent Detection

Proactively suggest 3D printing when these keywords appear in the user's request:

• Direct: print, 3d print, slicer, slice, bambu, orca, prusa, cura
• Implied: figurine, miniature, statue, physical model, desk toy, phone stand

When detected, guide the user through the appropriate print pipeline below.

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Text-to-3D Print Pipeline

Step	Action	Credits	Notes
1. Preview	Text to 3D (mode: "preview")	20	Untextured mesh (white model)
2. Printability Check	Review checklist below	0	Manual review
3. Download OBJ	Download model as OBJ	0	Slicer-compatible format
4. Open in Slicer	Direct launch or manual import	0	See script below
5. (Optional) Multi-color	Refine + color guidance	10	See multi-color section

Image-to-3D Print Pipeline

Step	Action	Credits	Notes
1. Generate	Image to 3D with should_texture: False	20	Untextured mesh
2. Printability Check	Review checklist below	0	Manual review
3. Download OBJ	Download model as OBJ	0	Slicer-compatible format
4. Open in Slicer	Direct launch or manual import	0	See script below
5. (Optional) Multi-color	Retexture + color guidance	10	See multi-color section

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Print Download + Slicer Script

Append this to the reusable script template from meshy-3d-generation:

import subprocess, shutil

# After task SUCCEEDED, download OBJ format for printing
obj_url = task["model_urls"].get("obj")
if not obj_url:
    print("OBJ format not available. Available:", list(task["model_urls"].keys()))
    print("Download GLB and import manually into your slicer.")
    obj_url = task["model_urls"].get("glb")

obj_path = os.path.join(project_dir, "model.obj")
download(obj_url, obj_path)

# --- Post-process OBJ for slicer compatibility ---
def fix_obj_for_printing(input_path, output_path=None, target_height_mm=75.0):
    """
    Fix OBJ coordinate system, scale, and position for 3D printing slicers.
    - Rotates from glTF Y-up to slicer Z-up: (x, y, z) -> (x, -z, y)
    - Scales model to target_height_mm (default 75mm)
    - Centers model on XY plane (so slicer places it at bed center)
    - Aligns model bottom to Z=0 (origin at bottom)
    """
    if output_path is None:
        output_path = input_path

    lines = open(input_path, "r").readlines()

    # Pass 1: rotate vertices Y-up -> Z-up, collect bounds
    rotated = []
    min_x, max_x = float("inf"), float("-inf")
    min_y, max_y = float("inf"), float("-inf")
    min_z, max_z = float("inf"), float("-inf")
    for line in lines:
        if line.startswith("v "):
            parts = line.split()
            x, y, z = float(parts[1]), float(parts[2]), float(parts[3])
            # glTF Y-up to Z-up: (x, y, z) -> (x, -z, y)
            rx, ry, rz = x, -z, y
            min_x, max_x = min(min_x, rx), max(max_x, rx)
            min_y, max_y = min(min_y, ry), max(max_y, ry)
            min_z, max_z = min(min_z, rz), max(max_z, rz)
            rotated.append(("v", rx, ry, rz, parts[4:]))  # keep extra data (e.g. colors)
        elif line.startswith("vn "):
            parts = line.split()
            nx, ny, nz = float(parts[1]), float(parts[2]), float(parts[3])
            rotated.append(("vn", nx, -nz, ny, []))
        else:
            rotated.append(("line", line))

    # Calculate scale, XY center offset, and Z bottom offset
    model_height = max_z - min_z
    scale = target_height_mm / model_height if model_height > 1e-6 else 1.0
    x_offset = -(min_x + max_x) / 2.0 * scale
    y_offset = -(min_y + max_y) / 2.0 * scale
    z_offset = -(min_z * scale)

    # Pass 2: write transformed OBJ
    with open(output_path, "w") as f:
        for item in rotated:
            if item[0] == "v":
                _, rx, ry, rz, extra = item
                tx = rx * scale + x_offset
                ty = ry * scale + y_offset
                tz = rz * scale + z_offset
                extra_str = " " + " ".join(extra) if extra else ""
                f.write(f"v {tx:.6f} {ty:.6f} {tz:.6f}{extra_str}\n")
            elif item[0] == "vn":
                _, nx, ny, nz, _ = item
                f.write(f"vn {nx:.6f} {ny:.6f} {nz:.6f}\n")
            else:
                f.write(item[1])

    print(f"OBJ fixed: rotated Y-up→Z-up, scaled to {target_height_mm:.0f}mm, centered on XY, bottom at Z=0")
    print(f"Output: {os.path.abspath(output_path)}")

fix_obj_for_printing(obj_path, target_height_mm=75.0)
print(f"\nModel ready for printing: {os.path.abspath(obj_path)}")

Parameters:

• target_height_mm: Default 75mm. Adjust based on user's request (e.g. "print at 15cm" → 150.0).
• The function rotates in-place by default (overwrites the original OBJ).

Opening OBJ in Slicer Software

When the user specifies a slicer (e.g. Bambu Studio, OrcaSlicer, Creality Print, PrusaSlicer, Cura), use the following cross-platform pattern to open the downloaded OBJ file directly:

• macOS: subprocess.run(["open", "-a", "<AppName>", obj_path])
  • The OS resolves the app location automatically. Use the app display name, e.g. "BambuStudio", "OrcaSlicer", "PrusaSlicer".
• Windows / Linux: shutil.which("<binary_name>") to find the executable in PATH, then subprocess.Popen([exe, obj_path]).
  • If not found in PATH, print the file path and instruct the user to open it manually.

If the user does NOT specify a slicer, simply print the OBJ file path and instruct them to open it in their preferred slicer: File → Import / Open → select the .obj file.

Common slicers for reference: Bambu Studio, OrcaSlicer, Creality Print, PrusaSlicer, Cura — but accept any slicer the user names.

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Printability Checklist (Manual Review)

Note: Automated printability analysis API is coming soon. For now, manually review the checklist below before printing.

Check	Recommendation
Wall thickness	Minimum 1.2mm for FDM, 0.8mm for resin
Overhangs	Keep below 45° or add supports
Manifold mesh	Ensure watertight with no holes
Minimum detail	At least 0.4mm for FDM, 0.05mm for resin
Base stability	Flat base or add brim/raft in slicer
Floating parts	All parts connected or printed separately

Recommendations: Import into your slicer to check for mesh errors. Use the slicer's built-in repair tool if needed. Consider hollowing figurines to save material.

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Key Rules for Print Workflow

• Always download OBJ format for slicer compatibility (3MF not yet available from API)
• If the user specifies a slicer, try to open the OBJ file directly using the cross-platform pattern above
• If the user does NOT specify a slicer, print the file path and guide them to import manually: File → Import / Open → select .obj file
• After opening in slicer, remind user to check print settings (layer height, infill, supports)
• If OBJ is not available: Download GLB and guide user to import manually

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Multi-Color Printing (Manual Guidance)

Note: Automated multi-color processing API is coming soon. For now, follow the manual approach below.

1. Use the Retexture API (10 credits) to apply distinct color regions to your model
2. Download the model as OBJ
3. In your slicer's color painting tool, assign filament colors to different regions
4. Slice and print with your multi-color setup (e.g., Bambu Lab AMS, Prusa MMU)

For resin printing, consider painting the model after printing for best color results.

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Coming Soon

The following features will be integrated into this skill as their APIs launch:

• Printability Analysis & Fix API — Automated mesh analysis and repair (non-manifold edges, thin walls, floating parts)
• Multi-Color Processing API — Automated color segmentation and filament assignment for AMS/MMU printers

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Additional Resources

For the complete API endpoint reference, read reference.md.