Application: mm2ply

Overview

mm2ply is a command-line tool that exports the layers of a MOLA metric map (*.mm) file as PLY point cloud files. It converts metric map files into the widely-supported PLY format, making it easy to visualize and process point cloud data in various 3D viewers and processing tools.

Features

  • Exports all point cloud layers from a metric map file

  • Supports both ASCII and binary PLY formats

  • Preserves all point fields (coordinates, colors, intensities, etc.)

  • Automatic field name mapping for standard color attributes

  • Generic field handling for custom point cloud attributes

Usage

mm2ply -i <input.mm> [-o <output_prefix>] [-b]

Arguments

  • -i, --input <file.mm> (required): Input metric map file

  • -o, --output <prefix> (optional): Prefix for output PLY files. If not specified, uses the input filename without extension

  • -b, --binary (optional): Export in binary format instead of ASCII (default: ASCII)

Examples

Export a metric map to ASCII PLY files:

mm2ply -i mymap.mm

Export with a custom output prefix:

mm2ply -i mymap.mm -o processed/map

Export in binary format for smaller file sizes:

mm2ply -i mymap.mm -b

Output

The tool creates separate PLY files for each point cloud layer in the metric map. Files are named using the pattern:

<prefix>_<layer_name>.ply

For example, if your map contains layers named “raw” and “filtered”, you’ll get:

  • mymap_raw.ply

  • mymap_filtered.ply

Supported Point Fields

The tool automatically exports all point attributes, including:

  • Coordinates: x, y, z (float)

  • Colors: Automatically maps color_r/color_rf → red, color_g/color_gf → green, color_b/color_bf → blue

  • Custom float fields: Exported as float properties

  • Custom double fields: Exported as double properties

  • Custom uint16 fields: Exported as ushort properties

  • Custom uint8 fields: Exported as uchar properties