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Mslicer supports four different output formats, each designed for specific use cases and printer types. This page provides an overview of all formats to help you choose the right one for your needs.

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Supported Formats

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Raster Formats (Bitmap-based)

These formats encode each layer as compressed bitmap data, suitable for standard MSLA resin printers.

Chitu CTB

Encrypted format for Chitu-based printers

Elegoo GOO

Open format for Elegoo printers

NanoDLP

ZIP-based format with PNG layers

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Vector Format

SVG

Vector output for visualization and debugging

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Format Comparison

FeatureCTBGOONanoDLPSVG
File Extension.ctb.goo.nanodlp.svg
EncryptionYes (AES-256)NoNoN/A
CompressionRLERLEPNG/DeflateN/A
Preview ImagesYes (2 sizes)Yes (2 sizes)Yes (1 image)No
Per-Layer SettingsYesYesYesNo
Format TypeBinaryBinaryZIP ArchiveXML Text
File SizeSmallSmallMediumVariable
Remote SendYesYesNoNo

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Choosing the Right Format

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For Printing

Select your format based on your printer:
  • Chitu-based printers (Anycubic, Creality, etc.): Use CTB
  • Elegoo printers (Mars, Saturn series): Use GOO
  • NanoDLP software: Use NanoDLP
  • Custom/DIY printers: Use NanoDLP (most compatible)

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For Development & Debugging

  • Visualizing slice geometry: Use SVG to inspect the exact slice polygons
  • Verifying layer data: Use NanoDLP to extract readable PNG files

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Format Details

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Run-Length Encoding (RLE)

Both CTB and GOO formats use run-length encoding to compress layer data efficiently. This compression is optimized for the horizontal runs of pixels typical in 3D printing, resulting in very compact file sizes. The encoding stores:
  • Pixel value (grayscale level)
  • Run length (number of consecutive pixels with the same value)

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Encryption in CTB

The CTB format uses AES-256-CBC encryption with a hardcoded key to protect the format specification. Mslicer implements full encryption support for compatibility with Chitu-based printers.

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ZIP Container Format

NanoDLP uses a ZIP archive containing:
  • JSON metadata files (profile, plate, options)
  • PNG images for each layer
  • 3D preview image
This makes it the most human-readable format and easiest to debug.

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Performance

Mslicer is optimized for high-performance file generation:
  • CTB: Fast binary encoding with parallel layer processing
  • GOO: Fast binary encoding with parallel layer processing
  • NanoDLP: Optimized PNG compression for RLE data
  • SVG: Lightweight vector output with minimal processing
All formats benefit from Mslicer’s parallel slicing engine, often achieving 20× to 120× faster performance compared to other slicers.

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File Extensions

When saving files, Mslicer automatically uses the correct extension: 
# CTB format
mslicer model.stl -o output.ctb

# GOO format
mslicer model.stl -o output.goo

# NanoDLP format
mslicer model.stl -o output.nanodlp

# SVG format
mslicer model.stl -o output.svg
The format is automatically detected from the file extension.
  • UVtools - Post-processing and inspection tool for all raster formats
  • msla-thumbs - KDE thumbnail support for sliced files

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